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Provide a correct Python 3 solution for this coding contest problem. Given is a connected undirected graph with N vertices and M edges. The vertices are numbered 1 to N, and the edges are described by a grid of characters S. If S_{i,j} is `1`, there is an edge connecting Vertex i and j; otherwise, there is no such edge. Determine whether it is possible to divide the vertices into non-empty sets V_1, \dots, V_k such that the following condition is satisfied. If the answer is yes, find the maximum possible number of sets, k, in such a division. * Every edge connects two vertices belonging to two "adjacent" sets. More formally, for every edge (i,j), there exists 1\leq t\leq k-1 such that i\in V_t,j\in V_{t+1} or i\in V_{t+1},j\in V_t holds. Constraints * 2 \leq N \leq 200 * S_{i,j} is `0` or `1`. * S_{i,i} is `0`. * S_{i,j}=S_{j,i} * The given graph is connected. * N is an integer. Input Input is given from Standard Input in the following format: N S_{1,1}...S_{1,N} : S_{N,1}...S_{N,N} Output If it is impossible to divide the vertices into sets so that the condition is satisfied, print -1. Otherwise, print the maximum possible number of sets, k, in a division that satisfies the condition. Examples Input 2 01 10 Output 2 Input 3 011 101 110 Output -1 Input 6 010110 101001 010100 101000 100000 010000 Output 4
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"Correct Solution: ``` def bfs(dp, arr, i, visited): q = [] q.append(i) visited[i] = True while q: i = q.pop(0) visited[i] = True for j in arr[i]: if dp[j] == -1: dp[j] = dp[i] + 1 elif dp[i] == dp[j]: return -1 if visited[j] == False: visited[j] = True q.append(j) return 0 n=int(input()) i=0 arr=[] degree = [0]*n while i<n: s=input() a=[] for j,e in enumerate(s): if e=='1': a.append(j) degree[i]+=1 arr.append(a) i+=1 res = -1 ans = -1 for i in range(n): dp = [-1]*n visited=[False for x in range(n)] dp[i] = 1 res=bfs(dp, arr, i, visited) if res == 0: ans = max(ans , max(dp)) print(ans) ```
output
1
55,413
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Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response. Given is a connected undirected graph with N vertices and M edges. The vertices are numbered 1 to N, and the edges are described by a grid of characters S. If S_{i,j} is `1`, there is an edge connecting Vertex i and j; otherwise, there is no such edge. Determine whether it is possible to divide the vertices into non-empty sets V_1, \dots, V_k such that the following condition is satisfied. If the answer is yes, find the maximum possible number of sets, k, in such a division. * Every edge connects two vertices belonging to two "adjacent" sets. More formally, for every edge (i,j), there exists 1\leq t\leq k-1 such that i\in V_t,j\in V_{t+1} or i\in V_{t+1},j\in V_t holds. Constraints * 2 \leq N \leq 200 * S_{i,j} is `0` or `1`. * S_{i,i} is `0`. * S_{i,j}=S_{j,i} * The given graph is connected. * N is an integer. Input Input is given from Standard Input in the following format: N S_{1,1}...S_{1,N} : S_{N,1}...S_{N,N} Output If it is impossible to divide the vertices into sets so that the condition is satisfied, print -1. Otherwise, print the maximum possible number of sets, k, in a division that satisfies the condition. Examples Input 2 01 10 Output 2 Input 3 011 101 110 Output -1 Input 6 010110 101001 010100 101000 100000 010000 Output 4 Submitted Solution: ``` from collections import deque n = int(input()) s = [[int(c) for c in input().strip()] for _ in range(n)] def bfs(s, start): plan = deque([(start, 0)]) lengths = {} while len(plan) > 0: vertex, length = plan.popleft() if vertex in lengths: if (lengths[vertex] - length) % 2 != 0: return -1 else: lengths[vertex] = length plan.extend([(i, length + 1) for i, c in enumerate(s[vertex]) if c == 1 and i not in lengths]) return max(lengths.values()) bfs_result = 0 for start in range(n): res = bfs(s, start) if res < 0: bfs_result = -2 break elif res > bfs_result: bfs_result = res print(bfs_result + 1) ```
instruction
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55,414
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Yes
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55,414
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Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response. Given is a connected undirected graph with N vertices and M edges. The vertices are numbered 1 to N, and the edges are described by a grid of characters S. If S_{i,j} is `1`, there is an edge connecting Vertex i and j; otherwise, there is no such edge. Determine whether it is possible to divide the vertices into non-empty sets V_1, \dots, V_k such that the following condition is satisfied. If the answer is yes, find the maximum possible number of sets, k, in such a division. * Every edge connects two vertices belonging to two "adjacent" sets. More formally, for every edge (i,j), there exists 1\leq t\leq k-1 such that i\in V_t,j\in V_{t+1} or i\in V_{t+1},j\in V_t holds. Constraints * 2 \leq N \leq 200 * S_{i,j} is `0` or `1`. * S_{i,i} is `0`. * S_{i,j}=S_{j,i} * The given graph is connected. * N is an integer. Input Input is given from Standard Input in the following format: N S_{1,1}...S_{1,N} : S_{N,1}...S_{N,N} Output If it is impossible to divide the vertices into sets so that the condition is satisfied, print -1. Otherwise, print the maximum possible number of sets, k, in a division that satisfies the condition. Examples Input 2 01 10 Output 2 Input 3 011 101 110 Output -1 Input 6 010110 101001 010100 101000 100000 010000 Output 4 Submitted Solution: ``` from collections import deque N = int(input()) S = [list(map(int, input().strip())) for _ in range(N)] G = [[] for _ in range(N)] for i in range(N): for j in range(N): if S[i][j] == 1: G[i].append(j) #Bipartie Graph def is_bibarate(G): vst = [False] * N que = deque([0]) color = [0] * N color[0] = 1 while len(que): p = que.popleft() for q in list(G[p]): if color[q] == 0: color[q] = - color[p] que.append(q) elif color[q] == color[p]: return False return True #Warshal Floyd d = [[float('inf')] * N for _ in range(N)] for i in range(N): for j in range(N): if i == j: d[i][j] = 0 elif S[i][j] == 1: d[i][j] = 1 for k in range(N): for i in range(N): for j in range(N): d[i][j] = min(d[i][j],d[i][k] + d[k][j]) wf_ans = max([max(r) for r in d]) + 1 if is_bibarate(G): print(wf_ans) else: print(-1) ```
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Yes
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110,831
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response. Given is a connected undirected graph with N vertices and M edges. The vertices are numbered 1 to N, and the edges are described by a grid of characters S. If S_{i,j} is `1`, there is an edge connecting Vertex i and j; otherwise, there is no such edge. Determine whether it is possible to divide the vertices into non-empty sets V_1, \dots, V_k such that the following condition is satisfied. If the answer is yes, find the maximum possible number of sets, k, in such a division. * Every edge connects two vertices belonging to two "adjacent" sets. More formally, for every edge (i,j), there exists 1\leq t\leq k-1 such that i\in V_t,j\in V_{t+1} or i\in V_{t+1},j\in V_t holds. Constraints * 2 \leq N \leq 200 * S_{i,j} is `0` or `1`. * S_{i,i} is `0`. * S_{i,j}=S_{j,i} * The given graph is connected. * N is an integer. Input Input is given from Standard Input in the following format: N S_{1,1}...S_{1,N} : S_{N,1}...S_{N,N} Output If it is impossible to divide the vertices into sets so that the condition is satisfied, print -1. Otherwise, print the maximum possible number of sets, k, in a division that satisfies the condition. Examples Input 2 01 10 Output 2 Input 3 011 101 110 Output -1 Input 6 010110 101001 010100 101000 100000 010000 Output 4 Submitted Solution: ``` ''' 二部グラフ判定 ''' INFTY = 10**13 def floyd(): for k in range(N): for i in range(N): if d[i][k] == INFTY: continue for j in range(N): if d[k][j] == INFTY: continue d[i][j] = min(d[i][j], d[i][k] + d[k][j]) def dfs(v, c): color[v] = c for i in G[v]: if color[i] == c: return False if color[i] == 0 and not dfs(i, -c): return False # ds[v] += d return True def solve(): for i in range(N): if color[i] == 0: if not dfs(i, 1): return False return True N = int(input()) G = [[]for i in range(N)] color = [0 for i in range(N)] # ds = [1 for i in range(N)] d = [[0 if i == j else INFTY for j in range(N)]for i in range(N)] for i in range(N): S = input() for j, s in enumerate(S): if s == '1': G[i].append(j) d[i][j] = 1 ans = solve() if ans: floyd() print(max([max(di)for di in d])+1) # print(max(ds)) else: print(-1) ```
instruction
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Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response. Given is a connected undirected graph with N vertices and M edges. The vertices are numbered 1 to N, and the edges are described by a grid of characters S. If S_{i,j} is `1`, there is an edge connecting Vertex i and j; otherwise, there is no such edge. Determine whether it is possible to divide the vertices into non-empty sets V_1, \dots, V_k such that the following condition is satisfied. If the answer is yes, find the maximum possible number of sets, k, in such a division. * Every edge connects two vertices belonging to two "adjacent" sets. More formally, for every edge (i,j), there exists 1\leq t\leq k-1 such that i\in V_t,j\in V_{t+1} or i\in V_{t+1},j\in V_t holds. Constraints * 2 \leq N \leq 200 * S_{i,j} is `0` or `1`. * S_{i,i} is `0`. * S_{i,j}=S_{j,i} * The given graph is connected. * N is an integer. Input Input is given from Standard Input in the following format: N S_{1,1}...S_{1,N} : S_{N,1}...S_{N,N} Output If it is impossible to divide the vertices into sets so that the condition is satisfied, print -1. Otherwise, print the maximum possible number of sets, k, in a division that satisfies the condition. Examples Input 2 01 10 Output 2 Input 3 011 101 110 Output -1 Input 6 010110 101001 010100 101000 100000 010000 Output 4 Submitted Solution: ``` n = int(input()) connect_matrix = [ list(input()) for i in range(n) ] def bfs(x): node_set = [ None for i in range(n)] color_list = [ "White" for i in range(n) ] search_list = [x] d = 0 node_set[x] = 0 color_list[x] = "Black" ans = 0 while search_list != []: d += 1 new_search_list = [] for i in search_list: for j, v in enumerate(connect_matrix[i]): if v == "1": if color_list[j] == "White": if node_set[j] is None: node_set[j] = node_set[i] + 1 new_search_list.append(j) color_list[j] = "Black" else: if (node_set[j] + node_set[i]) % 2 == 0: ans = -1 search_list = new_search_list return ans, d-1 judge_list = [] dist_list = [] for i in range(n): a = bfs(i) judge_list.append(a[0]) dist_list.append(a[1]) if -1 in judge_list: print(-1) else: print(max(dist_list)+1) ```
instruction
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Yes
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Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response. Given is a connected undirected graph with N vertices and M edges. The vertices are numbered 1 to N, and the edges are described by a grid of characters S. If S_{i,j} is `1`, there is an edge connecting Vertex i and j; otherwise, there is no such edge. Determine whether it is possible to divide the vertices into non-empty sets V_1, \dots, V_k such that the following condition is satisfied. If the answer is yes, find the maximum possible number of sets, k, in such a division. * Every edge connects two vertices belonging to two "adjacent" sets. More formally, for every edge (i,j), there exists 1\leq t\leq k-1 such that i\in V_t,j\in V_{t+1} or i\in V_{t+1},j\in V_t holds. Constraints * 2 \leq N \leq 200 * S_{i,j} is `0` or `1`. * S_{i,i} is `0`. * S_{i,j}=S_{j,i} * The given graph is connected. * N is an integer. Input Input is given from Standard Input in the following format: N S_{1,1}...S_{1,N} : S_{N,1}...S_{N,N} Output If it is impossible to divide the vertices into sets so that the condition is satisfied, print -1. Otherwise, print the maximum possible number of sets, k, in a division that satisfies the condition. Examples Input 2 01 10 Output 2 Input 3 011 101 110 Output -1 Input 6 010110 101001 010100 101000 100000 010000 Output 4 Submitted Solution: ``` #!/usr/bin/env python3 import sys INF = float("inf") from collections import deque def solve(N: int, S: "List[List[int]]"): visited = [False]*N q = deque() q.append(0) while len(q) > 0: node = q.popleft() visited[node] = True for to_, ex in enumerate(S[node]): if ex == 0: continue if visited[to_] is False: q.append(to_) depth = [INF]*N q = deque() q.append((node, 1)) while len(q) > 0: node, d = q.popleft() depth[node] = d # print(node, S[node]) for to_, ex in enumerate(S[node]): if ex == 0: continue if depth[to_] == INF: q.append((to_, d+1)) elif depth[to_] == d+1 or depth[to_] == d-1: continue else: # print(depth) print(-1) return # print(q) print(max(depth)) return def main(): def iterate_tokens(): for line in sys.stdin: for word in line.split(): yield word tokens = iterate_tokens() N = int(next(tokens)) # type: int S = [[int(c) for c in next(tokens)] for _ in range(N)] # type: "List[List[int]]" solve(N, S) if __name__ == '__main__': main() ```
instruction
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No
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Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response. Given is a connected undirected graph with N vertices and M edges. The vertices are numbered 1 to N, and the edges are described by a grid of characters S. If S_{i,j} is `1`, there is an edge connecting Vertex i and j; otherwise, there is no such edge. Determine whether it is possible to divide the vertices into non-empty sets V_1, \dots, V_k such that the following condition is satisfied. If the answer is yes, find the maximum possible number of sets, k, in such a division. * Every edge connects two vertices belonging to two "adjacent" sets. More formally, for every edge (i,j), there exists 1\leq t\leq k-1 such that i\in V_t,j\in V_{t+1} or i\in V_{t+1},j\in V_t holds. Constraints * 2 \leq N \leq 200 * S_{i,j} is `0` or `1`. * S_{i,i} is `0`. * S_{i,j}=S_{j,i} * The given graph is connected. * N is an integer. Input Input is given from Standard Input in the following format: N S_{1,1}...S_{1,N} : S_{N,1}...S_{N,N} Output If it is impossible to divide the vertices into sets so that the condition is satisfied, print -1. Otherwise, print the maximum possible number of sets, k, in a division that satisfies the condition. Examples Input 2 01 10 Output 2 Input 3 011 101 110 Output -1 Input 6 010110 101001 010100 101000 100000 010000 Output 4 Submitted Solution: ``` import sys #input = sys.stdin.buffer.readline from collections import deque def main(): N = int(input()) edge = [list(str(input())) for _ in range(N)] dist = [-1 for _ in range(N)] dist[0] = 0 q = deque([0]) D,e = 0,0 while q: now = q.popleft() for i in range(N): if edge[now][i] == "1": fol = i if dist[fol] == -1: dist[fol] = dist[now]+1 if dist[fol] > D: e = fol dist[fol] %= 2 q.append(fol) elif dist[now] == dist[fol]: print(-1) exit() q = deque([e]) dist = [-1 for _ in range(N)] dist[e] = 0 while q: now = q.pop() for i in range(N): if edge[now][i] == "1": fol = i if dist[fol] == -1: dist[fol] = dist[now]+1 q.append(fol) print(max(dist)+1) if __name__ == "__main__": main() ```
instruction
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Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response. Given is a connected undirected graph with N vertices and M edges. The vertices are numbered 1 to N, and the edges are described by a grid of characters S. If S_{i,j} is `1`, there is an edge connecting Vertex i and j; otherwise, there is no such edge. Determine whether it is possible to divide the vertices into non-empty sets V_1, \dots, V_k such that the following condition is satisfied. If the answer is yes, find the maximum possible number of sets, k, in such a division. * Every edge connects two vertices belonging to two "adjacent" sets. More formally, for every edge (i,j), there exists 1\leq t\leq k-1 such that i\in V_t,j\in V_{t+1} or i\in V_{t+1},j\in V_t holds. Constraints * 2 \leq N \leq 200 * S_{i,j} is `0` or `1`. * S_{i,i} is `0`. * S_{i,j}=S_{j,i} * The given graph is connected. * N is an integer. Input Input is given from Standard Input in the following format: N S_{1,1}...S_{1,N} : S_{N,1}...S_{N,N} Output If it is impossible to divide the vertices into sets so that the condition is satisfied, print -1. Otherwise, print the maximum possible number of sets, k, in a division that satisfies the condition. Examples Input 2 01 10 Output 2 Input 3 011 101 110 Output -1 Input 6 010110 101001 010100 101000 100000 010000 Output 4 Submitted Solution: ``` import collections import sys sys.setrecursionlimit(10**8) n=int(input()) arr=[input() for _ in range(n)] g=[[] for _ in range(n)] for i in range(n): for j in range(n): if i==j: continue if arr[i][j]=='1': g[i].append(j) colors=[0]*n def dfs(v,color): colors[v]=color for u in g[v]: if colors[u]==color: return False if colors[u]==0 and not dfs(u,-color): return False return True def is_bipartite(): return dfs(0,1) if is_bipartite()==False: print(-1) exit() ans=0 for v in range(n): q=collections.deque() q.append((v,1)) checked=[0]*n while len(q)!=0: tmp,depth=q.popleft() ans=max(ans,depth) checked[tmp]=1 for v in g[tmp]: if checked[v]==0: q.append((v,depth+1)) print(ans) ```
instruction
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No
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Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response. Given is a connected undirected graph with N vertices and M edges. The vertices are numbered 1 to N, and the edges are described by a grid of characters S. If S_{i,j} is `1`, there is an edge connecting Vertex i and j; otherwise, there is no such edge. Determine whether it is possible to divide the vertices into non-empty sets V_1, \dots, V_k such that the following condition is satisfied. If the answer is yes, find the maximum possible number of sets, k, in such a division. * Every edge connects two vertices belonging to two "adjacent" sets. More formally, for every edge (i,j), there exists 1\leq t\leq k-1 such that i\in V_t,j\in V_{t+1} or i\in V_{t+1},j\in V_t holds. Constraints * 2 \leq N \leq 200 * S_{i,j} is `0` or `1`. * S_{i,i} is `0`. * S_{i,j}=S_{j,i} * The given graph is connected. * N is an integer. Input Input is given from Standard Input in the following format: N S_{1,1}...S_{1,N} : S_{N,1}...S_{N,N} Output If it is impossible to divide the vertices into sets so that the condition is satisfied, print -1. Otherwise, print the maximum possible number of sets, k, in a division that satisfies the condition. Examples Input 2 01 10 Output 2 Input 3 011 101 110 Output -1 Input 6 010110 101001 010100 101000 100000 010000 Output 4 Submitted Solution: ``` n = int(input()) s = [] for _ in range(n): s.append(input()) check = [] testc = 1000 for i in range(n): test = 0 for c in s[i]: test += int(c) if test == testc: check.append(i) elif test < testc: check.clear() testc = test check.append(i) res = -1 if testc > 1: check = check[0] for i in check: tres = 1 flag = [-2 for i in range(n)] flag[i] = 1 que = [i] while que: target = que.pop() for j in range(n): if s[target][j] == "1": if flag[j] == -2: flag[j] = flag[target] + 1 que.append(j) elif flag[j] != flag[target] + 1 and flag[j] != flag[target] - 1: tres = -1 break if tres == -1: break if tres == -1: continue else: res = max(res, max(flag)) print(res) ```
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No
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Provide tags and a correct Python 3 solution for this coding contest problem. Today is tuesday, that means there is a dispute in JOHNNY SOLVING team again: they try to understand who is Johnny and who is Solving. That's why guys asked Umnik to help them. Umnik gave guys a connected graph with n vertices without loops and multiedges, such that a degree of any vertex is at least 3, and also he gave a number 1 ≤ k ≤ n. Because Johnny is not too smart, he promised to find a simple path with length at least n/k in the graph. In reply, Solving promised to find k simple by vertices cycles with representatives, such that: * Length of each cycle is at least 3. * Length of each cycle is not divisible by 3. * In each cycle must be a representative - vertex, which belongs only to this cycle among all printed cycles. You need to help guys resolve the dispute, for that you need to find a solution for Johnny: a simple path with length at least n/k (n is not necessarily divided by k), or solution for Solving: k cycles that satisfy all the conditions above. If there is no any solution - print -1. Input The first line contains three integers n, m and k (1 ≤ k ≤ n ≤ 2.5 ⋅ 10^5, 1 ≤ m ≤ 5 ⋅ 10^5) Next m lines describe edges of the graph in format v, u (1 ≤ v, u ≤ n). It's guaranteed that v ≠ u and all m pairs are distinct. It's guaranteed that a degree of each vertex is at least 3. Output Print PATH in the first line, if you solve problem for Johnny. In the second line print the number of vertices in the path c (c ≥ n/k). And in the third line print vertices describing the path in route order. Print CYCLES in the first line, if you solve problem for Solving. In the following lines describe exactly k cycles in the following format: in the first line print the size of the cycle c (c ≥ 3). In the second line print the cycle in route order. Also, the first vertex in the cycle must be a representative. Print -1 if there is no any solution. The total amount of printed numbers in the output must be at most 10^6. It's guaranteed, that if exists any solution then there is a correct output satisfies this restriction. Examples Input 4 6 2 1 2 1 3 1 4 2 3 2 4 3 4 Output PATH 4 1 2 3 4 Input 10 18 2 1 2 1 3 1 4 1 5 1 6 1 7 1 8 1 9 1 10 2 3 3 4 2 4 5 6 6 7 5 7 8 9 9 10 8 10 Output CYCLES 4 4 1 2 3 4 7 1 5 6
instruction
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Tags: constructive algorithms, dfs and similar, graphs, math Correct Solution: ``` import sys s = sys.stdin.read() inp = [] numb = 0 for i in range(len(s)): if s[i]>='0': numb = 10*numb + ord(s[i])-48 else: inp.append(numb) numb = 0 if s[-1]>='0': inp.append(numb) ii = 0 n = inp[ii] ii+=1 m = inp[ii] ii+=1 k = inp[ii] ii+=1 coupl = [[] for _ in range(n)] for _ in range(m): u = inp[ii]-1 ii += 1 v = inp[ii]-1 ii += 1 coupl[u].append(v) coupl[v].append(u) P = [-1]*n D = [1]*n found = [False]*n cycle_nodes = [] Q = [0] while Q: node = Q.pop() if found[node]: continue found[node] = True found_any = False for nei in coupl[node]: if not found[nei]: P[nei] = node D[nei] = D[node]+1 Q.append(nei) found_any = True if not found_any: cycle_nodes.append(node) i = max(range(n),key=lambda i:D[i]) if k*D[i]>=n: print('PATH') print(D[i]) out = [] while i!=-1: out.append(i) i = P[i] print(' '.join(str(x+1) for x in out)) elif len(cycle_nodes)>=k: print('CYCLES') out = [] for i in cycle_nodes[:k]: minD = min(D[nei] for nei in coupl[i] if (D[i] - D[nei] + 1)%3!=0) tmp = [] if minD == D[i]-1: a,b = [nei for nei in coupl[i] if (D[i] - D[nei] + 1)%3==0][:2] if D[a]<D[b]: a,b = b,a tmp.append(i) while a!=b: tmp.append(a) a = P[a] tmp.append(a) else: while D[i]!=minD: tmp.append(i) i = P[i] tmp.append(i) out.append(str(len(tmp))) out.append(' '.join(str(x+1) for x in tmp)) print('\n'.join(out)) else: print(-1) ```
output
1
55,647
13
111,295
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response. Today is tuesday, that means there is a dispute in JOHNNY SOLVING team again: they try to understand who is Johnny and who is Solving. That's why guys asked Umnik to help them. Umnik gave guys a connected graph with n vertices without loops and multiedges, such that a degree of any vertex is at least 3, and also he gave a number 1 ≤ k ≤ n. Because Johnny is not too smart, he promised to find a simple path with length at least n/k in the graph. In reply, Solving promised to find k simple by vertices cycles with representatives, such that: * Length of each cycle is at least 3. * Length of each cycle is not divisible by 3. * In each cycle must be a representative - vertex, which belongs only to this cycle among all printed cycles. You need to help guys resolve the dispute, for that you need to find a solution for Johnny: a simple path with length at least n/k (n is not necessarily divided by k), or solution for Solving: k cycles that satisfy all the conditions above. If there is no any solution - print -1. Input The first line contains three integers n, m and k (1 ≤ k ≤ n ≤ 2.5 ⋅ 10^5, 1 ≤ m ≤ 5 ⋅ 10^5) Next m lines describe edges of the graph in format v, u (1 ≤ v, u ≤ n). It's guaranteed that v ≠ u and all m pairs are distinct. It's guaranteed that a degree of each vertex is at least 3. Output Print PATH in the first line, if you solve problem for Johnny. In the second line print the number of vertices in the path c (c ≥ n/k). And in the third line print vertices describing the path in route order. Print CYCLES in the first line, if you solve problem for Solving. In the following lines describe exactly k cycles in the following format: in the first line print the size of the cycle c (c ≥ 3). In the second line print the cycle in route order. Also, the first vertex in the cycle must be a representative. Print -1 if there is no any solution. The total amount of printed numbers in the output must be at most 10^6. It's guaranteed, that if exists any solution then there is a correct output satisfies this restriction. Examples Input 4 6 2 1 2 1 3 1 4 2 3 2 4 3 4 Output PATH 4 1 2 3 4 Input 10 18 2 1 2 1 3 1 4 1 5 1 6 1 7 1 8 1 9 1 10 2 3 3 4 2 4 5 6 6 7 5 7 8 9 9 10 8 10 Output CYCLES 4 4 1 2 3 4 7 1 5 6 Submitted Solution: ``` [n, m, k] = [int(t) for t in input().split(' ')] e = [[] for _ in range(n)] for _ in range(m): [v1, v2] = [int(v) - 1 for v in input().split(' ')] e[v1].append(v2) e[v2].append(v1) from_ = [None] * n depths = [0] * n leaves = [] def path_found(v): print('PATH\n', depths[v]) while v != 0: print(v+1, end=' ') v = from_[v] print() exit() def print_path(v, up): while v != up: print(v+1, end=' ') v = from_[v] print(up+1) def print_cycle(v): [v1, v2] = [nv for nv in e[v] if nv != from_[v]] len1 = depths[v] - depths[v1] len2 = depths[v] - depths[v2] if len1 % 3 != 0: print(len1) return print_path(v, v1) if len2 % 3 != 0: print(len2) return print_path(v, v2) print(max(len1, len2) - min(len1, len2) + 2) print(v+1, end=' ') print_path(v1, v2) def dfs(v, depth): depths[v] = depth if depth >= n // k: return path_found(v) is_leaf = True for nv in e[v]: if from_[nv] is None: is_leaf = False from_[nv] = v dfs(nv, depth + 1) if is_leaf: leaves.append(v) from_[0] = 0 dfs(0, 1) if len(leaves) < k: print(-1) else: print('CYCLES') for i in range(k): print_cycle(leaves[i]) ```
instruction
0
55,648
13
111,296
No
output
1
55,648
13
111,297
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response. Today is tuesday, that means there is a dispute in JOHNNY SOLVING team again: they try to understand who is Johnny and who is Solving. That's why guys asked Umnik to help them. Umnik gave guys a connected graph with n vertices without loops and multiedges, such that a degree of any vertex is at least 3, and also he gave a number 1 ≤ k ≤ n. Because Johnny is not too smart, he promised to find a simple path with length at least n/k in the graph. In reply, Solving promised to find k simple by vertices cycles with representatives, such that: * Length of each cycle is at least 3. * Length of each cycle is not divisible by 3. * In each cycle must be a representative - vertex, which belongs only to this cycle among all printed cycles. You need to help guys resolve the dispute, for that you need to find a solution for Johnny: a simple path with length at least n/k (n is not necessarily divided by k), or solution for Solving: k cycles that satisfy all the conditions above. If there is no any solution - print -1. Input The first line contains three integers n, m and k (1 ≤ k ≤ n ≤ 2.5 ⋅ 10^5, 1 ≤ m ≤ 5 ⋅ 10^5) Next m lines describe edges of the graph in format v, u (1 ≤ v, u ≤ n). It's guaranteed that v ≠ u and all m pairs are distinct. It's guaranteed that a degree of each vertex is at least 3. Output Print PATH in the first line, if you solve problem for Johnny. In the second line print the number of vertices in the path c (c ≥ n/k). And in the third line print vertices describing the path in route order. Print CYCLES in the first line, if you solve problem for Solving. In the following lines describe exactly k cycles in the following format: in the first line print the size of the cycle c (c ≥ 3). In the second line print the cycle in route order. Also, the first vertex in the cycle must be a representative. Print -1 if there is no any solution. The total amount of printed numbers in the output must be at most 10^6. It's guaranteed, that if exists any solution then there is a correct output satisfies this restriction. Examples Input 4 6 2 1 2 1 3 1 4 2 3 2 4 3 4 Output PATH 4 1 2 3 4 Input 10 18 2 1 2 1 3 1 4 1 5 1 6 1 7 1 8 1 9 1 10 2 3 3 4 2 4 5 6 6 7 5 7 8 9 9 10 8 10 Output CYCLES 4 4 1 2 3 4 7 1 5 6 Submitted Solution: ``` [n, m, k] = [int(t) for t in input().split(' ')] e = [None] * n for _ in range(m): [v1, v2] = [int(v) - 1 for v in input().split(' ')] if e[v1] is None: e[v1] = [] if e[v2] is None: e[v2] = [] e[v1].append(v2) e[v2].append(v1) from_ = [None] * n leaves = [] def tear_up(v): path = [] while True: path.append(str(v+1)) if v == from_[v]: break v = from_[v] return path def path_found(v, depth): print('PATH') path = tear_up(v) print(len(path)) print(' '.join(path)) exit() def get_length(v, end): t = 1 while v != end: v = from_[v] t += 1 return t def print_path(v, up): while v != up: print(v+1, end=' ') v = from_[v] print(up+1) def print_cycle(v): nv = [nv for nv in e[v] if nv != from_[v]] len1 = get_length(v, nv[0]) if len1 % 3 != 0: return print_path(v, nv[0]) len2 = get_length(v, nv[1]) if len2 % 3 != 0: return print_path(v, nv[1]) print(v+1, end=' ') print_path(nv[0], nv[1]) def dfs(v, depth): if depth >= n // k: return path_found(v, depth) is_leaf = True for nv in e[v]: if from_[nv] is None: is_leaf = False from_[nv] = v dfs(nv, depth + 1) if is_leaf: leaves.append(v) from_[0] = 0 dfs(0, 1) if len(leaves) < k: print(-1) else: print('CYCLES') for i in range(k): print_cycle(leaves[i]) ```
instruction
0
55,649
13
111,298
No
output
1
55,649
13
111,299
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response. You are given a positive integer n. Let's build a graph on vertices 1, 2, ..., n in such a way that there is an edge between vertices u and v if and only if <image>. Let d(u, v) be the shortest distance between u and v, or 0 if there is no path between them. Compute the sum of values d(u, v) over all 1 ≤ u < v ≤ n. The gcd (greatest common divisor) of two positive integers is the maximum positive integer that divides both of the integers. Input Single integer n (1 ≤ n ≤ 107). Output Print the sum of d(u, v) over all 1 ≤ u < v ≤ n. Examples Input 6 Output 8 Input 10 Output 44 Note All shortest paths in the first example: * <image> * <image> * <image> * <image> * <image> * <image> There are no paths between other pairs of vertices. The total distance is 2 + 1 + 1 + 2 + 1 + 1 = 8. Submitted Solution: ``` n=int(input()) s = 0 b = [1] * n c = [0] * n c[0] = 1 bad=set() nu = 0 for i in range(1,n): if c[i] == 0: j = i while j < n: if c[j] == 0: c[j] = i+1 j += i+1 if c[i] == i+1: if (i+1)*2 > n: bad.add(i+1) j = i st = 1 stt = 1 while j < n: b[j] *= i if st % (i+1) == 0: stt *= i+1 b[j] *= stt j += i+1 st += 1 sdt=0 ed = (n*(n-1)) // 2 for i in range(1,n): sdt += b[i] ed -= sdt sdv = 0 for i in range(2,n+1): for j in range(i+1,n+1): if c[i-1]*c[j-1] <= n: sdv += 1 else: if max(c[i-1],c[j-1])*2 > n: nu += 1 sdv = sdv - ed st = sdt - (n-1) - nu - sdv s = ed + sdv*2 + st*3 print(s) ```
instruction
0
56,125
13
112,250
No
output
1
56,125
13
112,251
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response. You are given a positive integer n. Let's build a graph on vertices 1, 2, ..., n in such a way that there is an edge between vertices u and v if and only if <image>. Let d(u, v) be the shortest distance between u and v, or 0 if there is no path between them. Compute the sum of values d(u, v) over all 1 ≤ u < v ≤ n. The gcd (greatest common divisor) of two positive integers is the maximum positive integer that divides both of the integers. Input Single integer n (1 ≤ n ≤ 107). Output Print the sum of d(u, v) over all 1 ≤ u < v ≤ n. Examples Input 6 Output 8 Input 10 Output 44 Note All shortest paths in the first example: * <image> * <image> * <image> * <image> * <image> * <image> There are no paths between other pairs of vertices. The total distance is 2 + 1 + 1 + 2 + 1 + 1 = 8. Submitted Solution: ``` from fractions import gcd #from pythonds.basic import Queue arr = list(range(1, int(input())+1)) #print(arr) d = {} q = [] for i in arr: for j in arr: if i != j and gcd(i, j) > 1: if i in d: d[i].append(j) else: d[i] = [j] #print(d) sum = 0 for i in d.keys(): a = [i] q.append([i, 0]) while len(q) > 0: [num, length] = q.pop() for l in d[num]: if l not in a: sum += length+1 q.append([l, length+1]) a.append(l) print(int(sum/2)) ```
instruction
0
56,126
13
112,252
No
output
1
56,126
13
112,253
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response. You are given a positive integer n. Let's build a graph on vertices 1, 2, ..., n in such a way that there is an edge between vertices u and v if and only if <image>. Let d(u, v) be the shortest distance between u and v, or 0 if there is no path between them. Compute the sum of values d(u, v) over all 1 ≤ u < v ≤ n. The gcd (greatest common divisor) of two positive integers is the maximum positive integer that divides both of the integers. Input Single integer n (1 ≤ n ≤ 107). Output Print the sum of d(u, v) over all 1 ≤ u < v ≤ n. Examples Input 6 Output 8 Input 10 Output 44 Note All shortest paths in the first example: * <image> * <image> * <image> * <image> * <image> * <image> There are no paths between other pairs of vertices. The total distance is 2 + 1 + 1 + 2 + 1 + 1 = 8. Submitted Solution: ``` import math n = int(input()) gr = [] kek = 0 for i in range(n): gr.append([]) for ii in range(n): if i == ii: gr[i].append(0) elif math.gcd(i+1,ii+1) != 1: gr[i].append(1) else: gr[i].append(0) for i in range(1,n-1): for k in range(i+1,n): if gr[i][k] == 0: for j in range(1,n): if gr[i][j] and gr[j][k]: kek += 2 break else: for j in range(1,n): for t in range(1,n): if gr[i][j] and gr[j][t] and gr[t][k]: kek += 3 break else: kek += 1 print(kek) ```
instruction
0
56,127
13
112,254
No
output
1
56,127
13
112,255
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response. You are given a positive integer n. Let's build a graph on vertices 1, 2, ..., n in such a way that there is an edge between vertices u and v if and only if <image>. Let d(u, v) be the shortest distance between u and v, or 0 if there is no path between them. Compute the sum of values d(u, v) over all 1 ≤ u < v ≤ n. The gcd (greatest common divisor) of two positive integers is the maximum positive integer that divides both of the integers. Input Single integer n (1 ≤ n ≤ 107). Output Print the sum of d(u, v) over all 1 ≤ u < v ≤ n. Examples Input 6 Output 8 Input 10 Output 44 Note All shortest paths in the first example: * <image> * <image> * <image> * <image> * <image> * <image> There are no paths between other pairs of vertices. The total distance is 2 + 1 + 1 + 2 + 1 + 1 = 8. Submitted Solution: ``` n=int(input()) s = 0 b = [1] * n c = [0] * n c[0] = 1 nu = 0 for i in range(1,n): if c[i] == 0: j = i while j < n: if c[j] == 0: c[j] = i+1 j += i+1 j = i st = 1 stt = 1 sst = (i+1) ** 2 while j < n: b[j] *= i if st % (i+1) == 0: stt *= i+1 if j+1 == sst: b[j] *= stt sst = sst *(i+1) k = j+sst while k < n: b[k] *= stt k += sst j += i+1 st += 1 sdt=0 ed = (n*(n-1)) // 2 for i in range(1,n): sdt += b[i] print(ed) ed -= sdt sdv = 0 for i in range(2,n+1): for j in range(i+1,n+1): if c[i-1]*c[j-1] <= n: sdv += 1 ## print(str(i)+' '+str(j)) else: if max(c[i-1],c[j-1])*2 > n: nu += 1 sdv = sdv - ed st = sdt - (n-1) - nu - sdv s = ed + sdv*2 + st*3 print(str(ed)+' '+str(sdv)+' '+str(st)+' '+str(nu)+' '+str(sdt)) print(' '.join(map(str,c))) print(' '.join(map(str,b))) print(s) ```
instruction
0
56,128
13
112,256
No
output
1
56,128
13
112,257
Provide a correct Python 3 solution for this coding contest problem. There is a simple directed graph G with N vertices, numbered 1, 2, \ldots, N. For each i and j (1 \leq i, j \leq N), you are given an integer a_{i, j} that represents whether there is a directed edge from Vertex i to j. If a_{i, j} = 1, there is a directed edge from Vertex i to j; if a_{i, j} = 0, there is not. Find the number of different directed paths of length K in G, modulo 10^9 + 7. We will also count a path that traverses the same edge multiple times. Constraints * All values in input are integers. * 1 \leq N \leq 50 * 1 \leq K \leq 10^{18} * a_{i, j} is 0 or 1. * a_{i, i} = 0 Input Input is given from Standard Input in the following format: N K a_{1, 1} \ldots a_{1, N} : a_{N, 1} \ldots a_{N, N} Output Print the number of different directed paths of length K in G, modulo 10^9 + 7. Examples Input 4 2 0 1 0 0 0 0 1 1 0 0 0 1 1 0 0 0 Output 6 Input 3 3 0 1 0 1 0 1 0 0 0 Output 3 Input 6 2 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 Output 1 Input 1 1 0 Output 0 Input 10 1000000000000000000 0 0 1 1 0 0 0 1 1 0 0 0 0 0 0 1 1 1 0 0 0 1 0 0 0 1 0 1 0 1 1 1 1 0 1 1 0 1 1 0 0 1 1 1 0 1 0 1 1 1 0 0 0 1 0 0 1 0 1 0 0 0 0 1 1 0 0 1 0 1 1 0 0 0 1 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 1 1 1 0 1 1 1 0 Output 957538352
instruction
0
56,243
13
112,486
"Correct Solution: ``` # coding: utf-8 # Your code here! MOD=10**9+7 def dot(a, b): res = [[0] * n for _ in range(n)] for i in range(n): for k, aik in enumerate(a[i]): for j,bkj in enumerate(b[k]): res[i][j] += aik*bkj res[i][j] %= MOD return res n,k = [int(i) for i in input().split()] A = [[int(i) for i in input().split()] for _ in range(n)] ans = [[0] * n for _ in range(n)] for i in range(n): ans[i][i] = 1 while k: k, i = divmod(k, 2) if i: ans = dot(ans, A) A = dot(A, A) res = 0 for i in range(n): for j in range(n): res += ans[i][j] res %= MOD print(res) ```
output
1
56,243
13
112,487
Provide a correct Python 3 solution for this coding contest problem. There is a simple directed graph G with N vertices, numbered 1, 2, \ldots, N. For each i and j (1 \leq i, j \leq N), you are given an integer a_{i, j} that represents whether there is a directed edge from Vertex i to j. If a_{i, j} = 1, there is a directed edge from Vertex i to j; if a_{i, j} = 0, there is not. Find the number of different directed paths of length K in G, modulo 10^9 + 7. We will also count a path that traverses the same edge multiple times. Constraints * All values in input are integers. * 1 \leq N \leq 50 * 1 \leq K \leq 10^{18} * a_{i, j} is 0 or 1. * a_{i, i} = 0 Input Input is given from Standard Input in the following format: N K a_{1, 1} \ldots a_{1, N} : a_{N, 1} \ldots a_{N, N} Output Print the number of different directed paths of length K in G, modulo 10^9 + 7. Examples Input 4 2 0 1 0 0 0 0 1 1 0 0 0 1 1 0 0 0 Output 6 Input 3 3 0 1 0 1 0 1 0 0 0 Output 3 Input 6 2 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 Output 1 Input 1 1 0 Output 0 Input 10 1000000000000000000 0 0 1 1 0 0 0 1 1 0 0 0 0 0 0 1 1 1 0 0 0 1 0 0 0 1 0 1 0 1 1 1 1 0 1 1 0 1 1 0 0 1 1 1 0 1 0 1 1 1 0 0 0 1 0 0 1 0 1 0 0 0 0 1 1 0 0 1 0 1 1 0 0 0 1 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 1 1 1 0 1 1 1 0 Output 957538352
instruction
0
56,244
13
112,488
"Correct Solution: ``` mod = 10**9+7 def mat_mul(A, B): # A,Bは正方行列とする C = [[0]*N for _ in range(N)] for i in range(N): for j in range(N): C[i][j] = sum(A[i][k] * B[k][j] for k in range(N)) % mod return C def matpow(A, n): B = [[0]*N for _ in range(N)] for i in range(N): B[i][i] = 1 while n > 0: if n & 1: B = mat_mul(A, B) A = mat_mul(A, A) n //= 2 return B if __name__ == "__main__": N, K = map(int, input().split()) A = [list(map(int, input().split())) for _ in range(N)] A = matpow(A, K) ans = 0 for a in A: ans = (ans + sum(a)) % mod print(ans) ```
output
1
56,244
13
112,489
Provide a correct Python 3 solution for this coding contest problem. There is a simple directed graph G with N vertices, numbered 1, 2, \ldots, N. For each i and j (1 \leq i, j \leq N), you are given an integer a_{i, j} that represents whether there is a directed edge from Vertex i to j. If a_{i, j} = 1, there is a directed edge from Vertex i to j; if a_{i, j} = 0, there is not. Find the number of different directed paths of length K in G, modulo 10^9 + 7. We will also count a path that traverses the same edge multiple times. Constraints * All values in input are integers. * 1 \leq N \leq 50 * 1 \leq K \leq 10^{18} * a_{i, j} is 0 or 1. * a_{i, i} = 0 Input Input is given from Standard Input in the following format: N K a_{1, 1} \ldots a_{1, N} : a_{N, 1} \ldots a_{N, N} Output Print the number of different directed paths of length K in G, modulo 10^9 + 7. Examples Input 4 2 0 1 0 0 0 0 1 1 0 0 0 1 1 0 0 0 Output 6 Input 3 3 0 1 0 1 0 1 0 0 0 Output 3 Input 6 2 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 Output 1 Input 1 1 0 Output 0 Input 10 1000000000000000000 0 0 1 1 0 0 0 1 1 0 0 0 0 0 0 1 1 1 0 0 0 1 0 0 0 1 0 1 0 1 1 1 1 0 1 1 0 1 1 0 0 1 1 1 0 1 0 1 1 1 0 0 0 1 0 0 1 0 1 0 0 0 0 1 1 0 0 1 0 1 1 0 0 0 1 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 1 1 1 0 1 1 1 0 Output 957538352
instruction
0
56,245
13
112,490
"Correct Solution: ``` import sys stdin = sys.stdin def ni(): return int(ns()) def na(): return list(map(int, stdin.readline().split())) def naa(N): return [na() for _ in range(N)] def ns(): return stdin.readline().rstrip() # ignore trailing spaces def matrix_cal(A, B, mod): a = len(A) b = len(A[0]) c = len(B) d = len(B[0]) assert(b == c) ans = [[0] * d for _ in range(a)] for aa in range(a): for dd in range(d): v = 0 for bb in range(b): v = (v + A[aa][bb] * B[bb][dd]) % mod ans[aa][dd] = v return ans def matrix_pow(A, n, mod=0): if n == 1: return A a = matrix_pow(A, n//2, mod) ans = matrix_cal(a, a, mod) if n % 2 == 1: ans = matrix_cal(ans, A, mod) return ans N, K = na() A = naa(N) mod = 10 ** 9 + 7 B = matrix_pow(A, K, mod) ans = 0 for i in range(N): for j in range(N): ans = (ans + B[i][j]) % mod print(ans) ```
output
1
56,245
13
112,491
Provide a correct Python 3 solution for this coding contest problem. There is a simple directed graph G with N vertices, numbered 1, 2, \ldots, N. For each i and j (1 \leq i, j \leq N), you are given an integer a_{i, j} that represents whether there is a directed edge from Vertex i to j. If a_{i, j} = 1, there is a directed edge from Vertex i to j; if a_{i, j} = 0, there is not. Find the number of different directed paths of length K in G, modulo 10^9 + 7. We will also count a path that traverses the same edge multiple times. Constraints * All values in input are integers. * 1 \leq N \leq 50 * 1 \leq K \leq 10^{18} * a_{i, j} is 0 or 1. * a_{i, i} = 0 Input Input is given from Standard Input in the following format: N K a_{1, 1} \ldots a_{1, N} : a_{N, 1} \ldots a_{N, N} Output Print the number of different directed paths of length K in G, modulo 10^9 + 7. Examples Input 4 2 0 1 0 0 0 0 1 1 0 0 0 1 1 0 0 0 Output 6 Input 3 3 0 1 0 1 0 1 0 0 0 Output 3 Input 6 2 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 Output 1 Input 1 1 0 Output 0 Input 10 1000000000000000000 0 0 1 1 0 0 0 1 1 0 0 0 0 0 0 1 1 1 0 0 0 1 0 0 0 1 0 1 0 1 1 1 1 0 1 1 0 1 1 0 0 1 1 1 0 1 0 1 1 1 0 0 0 1 0 0 1 0 1 0 0 0 0 1 1 0 0 1 0 1 1 0 0 0 1 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 1 1 1 0 1 1 1 0 Output 957538352
instruction
0
56,246
13
112,492
"Correct Solution: ``` n, kk = map(int, input().split()) AA = [list(map(int, input().split())) for _ in range(n)] mod = 10 ** 9 + 7 # nxnの行列積 def matrix_product(A, B): res = [[0] * n for _ in range(n)] for i in range(n): for k in range(n): for j in range(n): res[i][j] += A[i][k] * B[k][j] res[i][j] %= mod return res def matrix_exponents(A, t): res = [[0] * n for _ in range(n)] for i in range(n): res[i][i] = 1 while t: if t & 1 == 1: res = matrix_product(res, A) A = matrix_product(A, A) t //= 2 return res temp = matrix_exponents(AA, kk) ans = 0 for i in range(n): for j in range(n): ans += temp[i][j] ans %= mod print(ans) ```
output
1
56,246
13
112,493
Provide a correct Python 3 solution for this coding contest problem. There is a simple directed graph G with N vertices, numbered 1, 2, \ldots, N. For each i and j (1 \leq i, j \leq N), you are given an integer a_{i, j} that represents whether there is a directed edge from Vertex i to j. If a_{i, j} = 1, there is a directed edge from Vertex i to j; if a_{i, j} = 0, there is not. Find the number of different directed paths of length K in G, modulo 10^9 + 7. We will also count a path that traverses the same edge multiple times. Constraints * All values in input are integers. * 1 \leq N \leq 50 * 1 \leq K \leq 10^{18} * a_{i, j} is 0 or 1. * a_{i, i} = 0 Input Input is given from Standard Input in the following format: N K a_{1, 1} \ldots a_{1, N} : a_{N, 1} \ldots a_{N, N} Output Print the number of different directed paths of length K in G, modulo 10^9 + 7. Examples Input 4 2 0 1 0 0 0 0 1 1 0 0 0 1 1 0 0 0 Output 6 Input 3 3 0 1 0 1 0 1 0 0 0 Output 3 Input 6 2 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 Output 1 Input 1 1 0 Output 0 Input 10 1000000000000000000 0 0 1 1 0 0 0 1 1 0 0 0 0 0 0 1 1 1 0 0 0 1 0 0 0 1 0 1 0 1 1 1 1 0 1 1 0 1 1 0 0 1 1 1 0 1 0 1 1 1 0 0 0 1 0 0 1 0 1 0 0 0 0 1 1 0 0 1 0 1 1 0 0 0 1 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 1 1 1 0 1 1 1 0 Output 957538352
instruction
0
56,247
13
112,494
"Correct Solution: ``` from collections import defaultdict, deque, Counter from heapq import heappush, heappop, heapify import math import bisect import random from itertools import permutations, accumulate, combinations, product import sys import string from bisect import bisect_left, bisect_right from math import factorial, ceil, floor from operator import mul from functools import reduce sys.setrecursionlimit(2147483647) INF = 10 ** 20 def LI(): return list(map(int, sys.stdin.readline().split())) def I(): return int(sys.stdin.readline()) def LS(): return sys.stdin.buffer.readline().rstrip().decode('utf-8').split() def S(): return sys.stdin.buffer.readline().rstrip().decode('utf-8') def IR(n): return [I() for i in range(n)] def LIR(n): return [LI() for i in range(n)] def SR(n): return [S() for i in range(n)] def LSR(n): return [LS() for i in range(n)] def SRL(n): return [list(S()) for i in range(n)] def MSRL(n): return [[int(j) for j in list(S())] for i in range(n)] mod = 1000000007 n, k = LI() G = LIR(n) def mat_mul(a, b): I, J, K = len(a), len(b[0]), len(b) c = [[0] * J for _ in range(I)] for i in range(I): for j in range(J): for k in range(K): c[i][j] += a[i][k] * b[k][j] c[i][j] %= mod return c def mat_pow(x, n): y = [[0] * len(x) for _ in range(len(x))] for i in range(len(x)): y[i][i] = 1 while n > 0: if n & 1: y = mat_mul(x, y) x = mat_mul(x, x) n >>= 1 return y ans = 0 GG = mat_pow(G, k) for i in range(n): for j in range(n): ans += GG[i][j] print(ans % mod) ```
output
1
56,247
13
112,495
Provide a correct Python 3 solution for this coding contest problem. There is a simple directed graph G with N vertices, numbered 1, 2, \ldots, N. For each i and j (1 \leq i, j \leq N), you are given an integer a_{i, j} that represents whether there is a directed edge from Vertex i to j. If a_{i, j} = 1, there is a directed edge from Vertex i to j; if a_{i, j} = 0, there is not. Find the number of different directed paths of length K in G, modulo 10^9 + 7. We will also count a path that traverses the same edge multiple times. Constraints * All values in input are integers. * 1 \leq N \leq 50 * 1 \leq K \leq 10^{18} * a_{i, j} is 0 or 1. * a_{i, i} = 0 Input Input is given from Standard Input in the following format: N K a_{1, 1} \ldots a_{1, N} : a_{N, 1} \ldots a_{N, N} Output Print the number of different directed paths of length K in G, modulo 10^9 + 7. Examples Input 4 2 0 1 0 0 0 0 1 1 0 0 0 1 1 0 0 0 Output 6 Input 3 3 0 1 0 1 0 1 0 0 0 Output 3 Input 6 2 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 Output 1 Input 1 1 0 Output 0 Input 10 1000000000000000000 0 0 1 1 0 0 0 1 1 0 0 0 0 0 0 1 1 1 0 0 0 1 0 0 0 1 0 1 0 1 1 1 1 0 1 1 0 1 1 0 0 1 1 1 0 1 0 1 1 1 0 0 0 1 0 0 1 0 1 0 0 0 0 1 1 0 0 1 0 1 1 0 0 0 1 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 1 1 1 0 1 1 1 0 Output 957538352
instruction
0
56,248
13
112,496
"Correct Solution: ``` p = 10**9+7 def pow(X,k): if k==0: return [[1 if i==j else 0 for j in range(N)] for i in range(N)] if k==1: return X if k%2==0: Y = pow(X,k//2) Z = [[0 for _ in range(N)] for _ in range(N)] for i in range(N): for j in range(N): for m in range(N): Z[i][j] = (Z[i][j]+Y[i][m]*Y[m][j])%p return Z else: Y = pow(X,(k-1)//2) Z = [[0 for _ in range(N)] for _ in range(N)] for i in range(N): for j in range(N): for m in range(N): Z[i][j] = (Z[i][j]+Y[i][m]*Y[m][j])%p Z1 = [[0 for _ in range(N)] for _ in range(N)] for i in range(N): for j in range(N): for m in range(N): Z1[i][j] = (Z1[i][j]+Z[i][m]*X[m][j])%p return Z1 N,K = map(int,input().split()) A = [list(map(int,input().split())) for _ in range(N)] X = pow(A,K) cnt = 0 for i in range(N): for j in range(N): cnt = (cnt+X[i][j])%p print(int(cnt)) ```
output
1
56,248
13
112,497
Provide a correct Python 3 solution for this coding contest problem. There is a simple directed graph G with N vertices, numbered 1, 2, \ldots, N. For each i and j (1 \leq i, j \leq N), you are given an integer a_{i, j} that represents whether there is a directed edge from Vertex i to j. If a_{i, j} = 1, there is a directed edge from Vertex i to j; if a_{i, j} = 0, there is not. Find the number of different directed paths of length K in G, modulo 10^9 + 7. We will also count a path that traverses the same edge multiple times. Constraints * All values in input are integers. * 1 \leq N \leq 50 * 1 \leq K \leq 10^{18} * a_{i, j} is 0 or 1. * a_{i, i} = 0 Input Input is given from Standard Input in the following format: N K a_{1, 1} \ldots a_{1, N} : a_{N, 1} \ldots a_{N, N} Output Print the number of different directed paths of length K in G, modulo 10^9 + 7. Examples Input 4 2 0 1 0 0 0 0 1 1 0 0 0 1 1 0 0 0 Output 6 Input 3 3 0 1 0 1 0 1 0 0 0 Output 3 Input 6 2 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 Output 1 Input 1 1 0 Output 0 Input 10 1000000000000000000 0 0 1 1 0 0 0 1 1 0 0 0 0 0 0 1 1 1 0 0 0 1 0 0 0 1 0 1 0 1 1 1 1 0 1 1 0 1 1 0 0 1 1 1 0 1 0 1 1 1 0 0 0 1 0 0 1 0 1 0 0 0 0 1 1 0 0 1 0 1 1 0 0 0 1 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 1 1 1 0 1 1 1 0 Output 957538352
instruction
0
56,249
13
112,498
"Correct Solution: ``` import sys input = sys.stdin.readline def matDot(A,B,MOD): N,M,L = len(A),len(A[0]),len(B[0]) res = [[0]*L for i in range(N)] for i in range(N): for j in range(L): s = 0 for k in range(M): s = (s + A[i][k]*B[k][j]) % MOD res[i][j] = s return res def matPow(A,x,MOD): N = len(A) res = [[0]*N for i in range(N)] for i in range(N): res[i][i] = 1 for i in range(x.bit_length()): if (x>>i) & 1: res = matDot(res,A,MOD) A = matDot(A,A,MOD) return res n,k = map(int,input().split()) mod = 10**9+7 a = [] for i in range(n): a.append(tuple(map(int,input().split()))) b = matPow(a,k,mod) ans = 0 for i in range(n): for j in range(n): ans = (ans+b[i][j])%mod print(ans) ```
output
1
56,249
13
112,499
Provide a correct Python 3 solution for this coding contest problem. There is a simple directed graph G with N vertices, numbered 1, 2, \ldots, N. For each i and j (1 \leq i, j \leq N), you are given an integer a_{i, j} that represents whether there is a directed edge from Vertex i to j. If a_{i, j} = 1, there is a directed edge from Vertex i to j; if a_{i, j} = 0, there is not. Find the number of different directed paths of length K in G, modulo 10^9 + 7. We will also count a path that traverses the same edge multiple times. Constraints * All values in input are integers. * 1 \leq N \leq 50 * 1 \leq K \leq 10^{18} * a_{i, j} is 0 or 1. * a_{i, i} = 0 Input Input is given from Standard Input in the following format: N K a_{1, 1} \ldots a_{1, N} : a_{N, 1} \ldots a_{N, N} Output Print the number of different directed paths of length K in G, modulo 10^9 + 7. Examples Input 4 2 0 1 0 0 0 0 1 1 0 0 0 1 1 0 0 0 Output 6 Input 3 3 0 1 0 1 0 1 0 0 0 Output 3 Input 6 2 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 Output 1 Input 1 1 0 Output 0 Input 10 1000000000000000000 0 0 1 1 0 0 0 1 1 0 0 0 0 0 0 1 1 1 0 0 0 1 0 0 0 1 0 1 0 1 1 1 1 0 1 1 0 1 1 0 0 1 1 1 0 1 0 1 1 1 0 0 0 1 0 0 1 0 1 0 0 0 0 1 1 0 0 1 0 1 1 0 0 0 1 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 1 1 1 0 1 1 1 0 Output 957538352
instruction
0
56,250
13
112,500
"Correct Solution: ``` n,k = map(int,input().split()) g = [list(map(int,input().split())) for i in range(n)] mod = 10**9+7 ans = 0 def mul(x,y): res = [] for i in range(n): tmp = [] for j in range(n): ko = 0 for k in range(n): ko += x[i][k] * y[k][j] ko %=mod tmp.append(ko) res.append(tmp) return res while k>0: if k &1 ==1: if type(ans) is int: ans = g else: ans = mul(g,ans) g = mul(g,g) k >>= 1 res = 0 for i in range(n): for j in range(n): res += ans[i][j] res %= mod print(res) ```
output
1
56,250
13
112,501
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response. There is a simple directed graph G with N vertices, numbered 1, 2, \ldots, N. For each i and j (1 \leq i, j \leq N), you are given an integer a_{i, j} that represents whether there is a directed edge from Vertex i to j. If a_{i, j} = 1, there is a directed edge from Vertex i to j; if a_{i, j} = 0, there is not. Find the number of different directed paths of length K in G, modulo 10^9 + 7. We will also count a path that traverses the same edge multiple times. Constraints * All values in input are integers. * 1 \leq N \leq 50 * 1 \leq K \leq 10^{18} * a_{i, j} is 0 or 1. * a_{i, i} = 0 Input Input is given from Standard Input in the following format: N K a_{1, 1} \ldots a_{1, N} : a_{N, 1} \ldots a_{N, N} Output Print the number of different directed paths of length K in G, modulo 10^9 + 7. Examples Input 4 2 0 1 0 0 0 0 1 1 0 0 0 1 1 0 0 0 Output 6 Input 3 3 0 1 0 1 0 1 0 0 0 Output 3 Input 6 2 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 Output 1 Input 1 1 0 Output 0 Input 10 1000000000000000000 0 0 1 1 0 0 0 1 1 0 0 0 0 0 0 1 1 1 0 0 0 1 0 0 0 1 0 1 0 1 1 1 1 0 1 1 0 1 1 0 0 1 1 1 0 1 0 1 1 1 0 0 0 1 0 0 1 0 1 0 0 0 0 1 1 0 0 1 0 1 1 0 0 0 1 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 1 1 1 0 1 1 1 0 Output 957538352 Submitted Solution: ``` N,K = map(int,input().split()) G = [list(map(int,input().split())) for _ in range(N)] #print(G) MOD = 10**9+7 def dot(a,b): res = [[0] * N for _ in range(N)] for i in range(N): for j in range(N): res[i][j] = sum(a[i][k] * b[k][j] for k in range(N)) % MOD return res ans = [[0] * N for _ in range(N)] for i in range(N): ans[i][i] = 1 while(K>0): K,x = divmod(K,2) if x == 1: ans = dot(ans,G) G = dot(G,G) print(sum(sum(a) % MOD for a in ans) % MOD) ```
instruction
0
56,251
13
112,502
Yes
output
1
56,251
13
112,503
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response. There is a simple directed graph G with N vertices, numbered 1, 2, \ldots, N. For each i and j (1 \leq i, j \leq N), you are given an integer a_{i, j} that represents whether there is a directed edge from Vertex i to j. If a_{i, j} = 1, there is a directed edge from Vertex i to j; if a_{i, j} = 0, there is not. Find the number of different directed paths of length K in G, modulo 10^9 + 7. We will also count a path that traverses the same edge multiple times. Constraints * All values in input are integers. * 1 \leq N \leq 50 * 1 \leq K \leq 10^{18} * a_{i, j} is 0 or 1. * a_{i, i} = 0 Input Input is given from Standard Input in the following format: N K a_{1, 1} \ldots a_{1, N} : a_{N, 1} \ldots a_{N, N} Output Print the number of different directed paths of length K in G, modulo 10^9 + 7. Examples Input 4 2 0 1 0 0 0 0 1 1 0 0 0 1 1 0 0 0 Output 6 Input 3 3 0 1 0 1 0 1 0 0 0 Output 3 Input 6 2 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 Output 1 Input 1 1 0 Output 0 Input 10 1000000000000000000 0 0 1 1 0 0 0 1 1 0 0 0 0 0 0 1 1 1 0 0 0 1 0 0 0 1 0 1 0 1 1 1 1 0 1 1 0 1 1 0 0 1 1 1 0 1 0 1 1 1 0 0 0 1 0 0 1 0 1 0 0 0 0 1 1 0 0 1 0 1 1 0 0 0 1 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 1 1 1 0 1 1 1 0 Output 957538352 Submitted Solution: ``` mod = 10**9 + 7 N, K = map(int,input().split()) A = [list(map(int,input().split())) for _ in range(N)] def dot(X, Y): x = len(X) y = len(Y[0]) z = len(Y) C = [[0] * y for _ in range(x)] for i in range(x): for j in range(y): for k in range(z): C[i][j] += X[i][k] * Y[k][j] C[i][j] %= mod return C B = [[0] * N for _ in range(N)] for k in range(N): B[k][k] = 1 while K > 0: if K & 1: B = dot(B, A) A = dot(A, A) K >>= 1 ans = 0 for i in range(N): for j in range(N): ans += B[i][j] ans %= mod print(ans) ```
instruction
0
56,252
13
112,504
Yes
output
1
56,252
13
112,505
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response. There is a simple directed graph G with N vertices, numbered 1, 2, \ldots, N. For each i and j (1 \leq i, j \leq N), you are given an integer a_{i, j} that represents whether there is a directed edge from Vertex i to j. If a_{i, j} = 1, there is a directed edge from Vertex i to j; if a_{i, j} = 0, there is not. Find the number of different directed paths of length K in G, modulo 10^9 + 7. We will also count a path that traverses the same edge multiple times. Constraints * All values in input are integers. * 1 \leq N \leq 50 * 1 \leq K \leq 10^{18} * a_{i, j} is 0 or 1. * a_{i, i} = 0 Input Input is given from Standard Input in the following format: N K a_{1, 1} \ldots a_{1, N} : a_{N, 1} \ldots a_{N, N} Output Print the number of different directed paths of length K in G, modulo 10^9 + 7. Examples Input 4 2 0 1 0 0 0 0 1 1 0 0 0 1 1 0 0 0 Output 6 Input 3 3 0 1 0 1 0 1 0 0 0 Output 3 Input 6 2 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 Output 1 Input 1 1 0 Output 0 Input 10 1000000000000000000 0 0 1 1 0 0 0 1 1 0 0 0 0 0 0 1 1 1 0 0 0 1 0 0 0 1 0 1 0 1 1 1 1 0 1 1 0 1 1 0 0 1 1 1 0 1 0 1 1 1 0 0 0 1 0 0 1 0 1 0 0 0 0 1 1 0 0 1 0 1 1 0 0 0 1 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 1 1 1 0 1 1 1 0 Output 957538352 Submitted Solution: ``` #!/mnt/c/Users/moiki/bash/env/bin/python N,K = map(int, input().split()) A = [ [int(j) for j in input().split()] for i in range(N)] # I = [ [j for j in range(1,N+1) if Ai[j]] for Ai in A] MOD = 10**9 + 7 # dp = [0] * (N+1) dp = [ [0] * (N+1) for _ in range(N+1)] S = [[1]*N] KDIG = [0]*70 for i in range(1,61): if K % (1<<i) : KDIG[i-1] = 1 K -= K%(1<<i) def prod(A,B,k,l,m):#A:k*l,B:l*m C=[[None for i in range(m)] for j in range(k)] for i in range(k): for j in range(m): ANS=0 for pl in range(l): ANS=(ANS+A[i][pl]*B[pl][j])%MOD C[i][j]=ANS return C for i in range(60): if KDIG[i] == 1: S = prod(S,A,1,N,N) A = prod(A,A,N,N,N) print(sum(S[0])%MOD) # for i in range(1,N+1): # for j in range(1,N+1): # # dp[i][j] = np.linalg.matrix_power(A, K)[i-1][j-1].item() # # ans += dp[i][j] % MOD # # ans += np.linalg.matrix_power(A, K)[i-1][j-1].item() % MOD # # ans += M[i-1,j-1].item() % MOD # ans += M[i-1][j-1] % MOD # print(ans%MOD) ```
instruction
0
56,253
13
112,506
Yes
output
1
56,253
13
112,507
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response. There is a simple directed graph G with N vertices, numbered 1, 2, \ldots, N. For each i and j (1 \leq i, j \leq N), you are given an integer a_{i, j} that represents whether there is a directed edge from Vertex i to j. If a_{i, j} = 1, there is a directed edge from Vertex i to j; if a_{i, j} = 0, there is not. Find the number of different directed paths of length K in G, modulo 10^9 + 7. We will also count a path that traverses the same edge multiple times. Constraints * All values in input are integers. * 1 \leq N \leq 50 * 1 \leq K \leq 10^{18} * a_{i, j} is 0 or 1. * a_{i, i} = 0 Input Input is given from Standard Input in the following format: N K a_{1, 1} \ldots a_{1, N} : a_{N, 1} \ldots a_{N, N} Output Print the number of different directed paths of length K in G, modulo 10^9 + 7. Examples Input 4 2 0 1 0 0 0 0 1 1 0 0 0 1 1 0 0 0 Output 6 Input 3 3 0 1 0 1 0 1 0 0 0 Output 3 Input 6 2 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 Output 1 Input 1 1 0 Output 0 Input 10 1000000000000000000 0 0 1 1 0 0 0 1 1 0 0 0 0 0 0 1 1 1 0 0 0 1 0 0 0 1 0 1 0 1 1 1 1 0 1 1 0 1 1 0 0 1 1 1 0 1 0 1 1 1 0 0 0 1 0 0 1 0 1 0 0 0 0 1 1 0 0 1 0 1 1 0 0 0 1 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 1 1 1 0 1 1 1 0 Output 957538352 Submitted Solution: ``` mod = 10**9+7 n, K = map(int, input().split()) a = [[int(x) for x in input().split()] for _ in range(n)] A = [a] i = 1 while 2**i <= K: mtrix = [] for j in range(n): raw = [] for l in range(n): tmp = 0 for k in range(n): tmp += A[-1][j][k] * A[-1][k][l] raw.append(tmp % mod) mtrix.append(raw) A.append(mtrix) i += 1 bit_max = i ans = [[[0]*n for _ in range(n)]] for i in range(n): for j in range(n): if i == j: ans[-1][i][j] = 1 for i in range(bit_max): if (K >> i) & 1: mtrix = [] for j in range(n): raw = [] for l in range(n): tmp = 0 for k in range(n): tmp += ans[-1][j][k] * A[i][k][l] raw.append(tmp % mod) mtrix.append(raw) ans.append(mtrix) ans = sum(map(lambda x: sum(x) % mod, ans[-1])) print(ans % mod) ```
instruction
0
56,254
13
112,508
Yes
output
1
56,254
13
112,509
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response. There is a simple directed graph G with N vertices, numbered 1, 2, \ldots, N. For each i and j (1 \leq i, j \leq N), you are given an integer a_{i, j} that represents whether there is a directed edge from Vertex i to j. If a_{i, j} = 1, there is a directed edge from Vertex i to j; if a_{i, j} = 0, there is not. Find the number of different directed paths of length K in G, modulo 10^9 + 7. We will also count a path that traverses the same edge multiple times. Constraints * All values in input are integers. * 1 \leq N \leq 50 * 1 \leq K \leq 10^{18} * a_{i, j} is 0 or 1. * a_{i, i} = 0 Input Input is given from Standard Input in the following format: N K a_{1, 1} \ldots a_{1, N} : a_{N, 1} \ldots a_{N, N} Output Print the number of different directed paths of length K in G, modulo 10^9 + 7. Examples Input 4 2 0 1 0 0 0 0 1 1 0 0 0 1 1 0 0 0 Output 6 Input 3 3 0 1 0 1 0 1 0 0 0 Output 3 Input 6 2 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 Output 1 Input 1 1 0 Output 0 Input 10 1000000000000000000 0 0 1 1 0 0 0 1 1 0 0 0 0 0 0 1 1 1 0 0 0 1 0 0 0 1 0 1 0 1 1 1 1 0 1 1 0 1 1 0 0 1 1 1 0 1 0 1 1 1 0 0 0 1 0 0 1 0 1 0 0 0 0 1 1 0 0 1 0 1 1 0 0 0 1 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 1 1 1 0 1 1 1 0 Output 957538352 Submitted Solution: ``` n,k = map(int,input().split()) g = [list(map(int,input().split())) for i in range(n)] mod = 10**9+7 import numpy as np gyou = np.matrix(g) ans = np.eye(n).astype(int) ans = np.matrix(ans) while k: if k &1 ==1: ans = np.dot(ans,gyou) gyou = np.dot(gyou,gyou) k >>= 1 ans %=mod gyou %= mod print(np.sum(ans)%mod) ```
instruction
0
56,255
13
112,510
No
output
1
56,255
13
112,511
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response. There is a simple directed graph G with N vertices, numbered 1, 2, \ldots, N. For each i and j (1 \leq i, j \leq N), you are given an integer a_{i, j} that represents whether there is a directed edge from Vertex i to j. If a_{i, j} = 1, there is a directed edge from Vertex i to j; if a_{i, j} = 0, there is not. Find the number of different directed paths of length K in G, modulo 10^9 + 7. We will also count a path that traverses the same edge multiple times. Constraints * All values in input are integers. * 1 \leq N \leq 50 * 1 \leq K \leq 10^{18} * a_{i, j} is 0 or 1. * a_{i, i} = 0 Input Input is given from Standard Input in the following format: N K a_{1, 1} \ldots a_{1, N} : a_{N, 1} \ldots a_{N, N} Output Print the number of different directed paths of length K in G, modulo 10^9 + 7. Examples Input 4 2 0 1 0 0 0 0 1 1 0 0 0 1 1 0 0 0 Output 6 Input 3 3 0 1 0 1 0 1 0 0 0 Output 3 Input 6 2 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 Output 1 Input 1 1 0 Output 0 Input 10 1000000000000000000 0 0 1 1 0 0 0 1 1 0 0 0 0 0 0 1 1 1 0 0 0 1 0 0 0 1 0 1 0 1 1 1 1 0 1 1 0 1 1 0 0 1 1 1 0 1 0 1 1 1 0 0 0 1 0 0 1 0 1 0 0 0 0 1 1 0 0 1 0 1 1 0 0 0 1 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 1 1 1 0 1 1 1 0 Output 957538352 Submitted Solution: ``` import numpy as np import sys input = sys.stdin.readline mod = 10**9+7 N, K = map(int, input().split()) a = np.array([list(map(int, input().split())) for _ in range(N)], dtype=np.int64) ans = np.identity(N, dtype=np.int64) while K > 0: if K & 1 == 1: ans = np.matmul(ans, a) % mod a = np.matmul(a, a) % mod K >>= 1 print(np.sum(ans) % mod) ```
instruction
0
56,256
13
112,512
No
output
1
56,256
13
112,513
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response. There is a simple directed graph G with N vertices, numbered 1, 2, \ldots, N. For each i and j (1 \leq i, j \leq N), you are given an integer a_{i, j} that represents whether there is a directed edge from Vertex i to j. If a_{i, j} = 1, there is a directed edge from Vertex i to j; if a_{i, j} = 0, there is not. Find the number of different directed paths of length K in G, modulo 10^9 + 7. We will also count a path that traverses the same edge multiple times. Constraints * All values in input are integers. * 1 \leq N \leq 50 * 1 \leq K \leq 10^{18} * a_{i, j} is 0 or 1. * a_{i, i} = 0 Input Input is given from Standard Input in the following format: N K a_{1, 1} \ldots a_{1, N} : a_{N, 1} \ldots a_{N, N} Output Print the number of different directed paths of length K in G, modulo 10^9 + 7. Examples Input 4 2 0 1 0 0 0 0 1 1 0 0 0 1 1 0 0 0 Output 6 Input 3 3 0 1 0 1 0 1 0 0 0 Output 3 Input 6 2 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 Output 1 Input 1 1 0 Output 0 Input 10 1000000000000000000 0 0 1 1 0 0 0 1 1 0 0 0 0 0 0 1 1 1 0 0 0 1 0 0 0 1 0 1 0 1 1 1 1 0 1 1 0 1 1 0 0 1 1 1 0 1 0 1 1 1 0 0 0 1 0 0 1 0 1 0 0 0 0 1 1 0 0 1 0 1 1 0 0 0 1 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 1 1 1 0 1 1 1 0 Output 957538352 Submitted Solution: ``` from collections import deque from collections import Counter from itertools import product, permutations,combinations from operator import itemgetter from heapq import heappop, heappush from bisect import bisect_left, bisect_right, bisect #pypyではscipy, numpyは使えない #from scipy.sparse.csgraph import shortest_path, floyd_warshall, dijkstra, bellman_ford, johnson, minimum_spanning_tree #from scipy.sparse import csr_matrix, coo_matrix, lil_matrix import numpy as np from fractions import gcd from math import ceil,floor, sqrt, cos, sin, pi, factorial import sys read = sys.stdin.buffer.read readline = sys.stdin.buffer.readline readlines = sys.stdin.buffer.readlines #文字列のときはうまく行かないのでコメントアウトすること sys.setrecursionlimit(10**9) INF = float('inf') MOD = 10**9 +7 def main(): N, K = map(int, readline().split()) A = np.array(read().split(), np.int64).reshape(N,N) def pow_array(a,k):#行列aのk乗の計算 ans = np.eye(N) while k: if k%2: ans = np.dot(ans%MOD, a%MOD) a = np.dot(a%MOD, a%MOD) k>>=1 return ans%MOD anser = pow_array(A,K).astype('int64').sum() print(anser) if __name__ == '__main__': main() ```
instruction
0
56,257
13
112,514
No
output
1
56,257
13
112,515
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response. There is a simple directed graph G with N vertices, numbered 1, 2, \ldots, N. For each i and j (1 \leq i, j \leq N), you are given an integer a_{i, j} that represents whether there is a directed edge from Vertex i to j. If a_{i, j} = 1, there is a directed edge from Vertex i to j; if a_{i, j} = 0, there is not. Find the number of different directed paths of length K in G, modulo 10^9 + 7. We will also count a path that traverses the same edge multiple times. Constraints * All values in input are integers. * 1 \leq N \leq 50 * 1 \leq K \leq 10^{18} * a_{i, j} is 0 or 1. * a_{i, i} = 0 Input Input is given from Standard Input in the following format: N K a_{1, 1} \ldots a_{1, N} : a_{N, 1} \ldots a_{N, N} Output Print the number of different directed paths of length K in G, modulo 10^9 + 7. Examples Input 4 2 0 1 0 0 0 0 1 1 0 0 0 1 1 0 0 0 Output 6 Input 3 3 0 1 0 1 0 1 0 0 0 Output 3 Input 6 2 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 Output 1 Input 1 1 0 Output 0 Input 10 1000000000000000000 0 0 1 1 0 0 0 1 1 0 0 0 0 0 0 1 1 1 0 0 0 1 0 0 0 1 0 1 0 1 1 1 1 0 1 1 0 1 1 0 0 1 1 1 0 1 0 1 1 1 0 0 0 1 0 0 1 0 1 0 0 0 0 1 1 0 0 1 0 1 1 0 0 0 1 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 1 1 1 0 1 1 1 0 Output 957538352 Submitted Solution: ``` import numpy as np def main(): MOD = int(1e9 + 7) n, k = map(int, input().split()) can = [[int(c) for c in input().split()] for _ in range(n)] can = np.array(can) answer = np.eye(n) while k: if k % 2: answer = np.dot(answer, can) % MOD can = np.dot(can, can) % MOD k //= 2 total = 0 for i in range(n): for j in range(n): total += answer[i,j] if total >= MOD: total -= MOD print(total) if __name__ == "__main__": main() ```
instruction
0
56,258
13
112,516
No
output
1
56,258
13
112,517
Provide a correct Python 3 solution for this coding contest problem. Search trees are data structures that support dynamic set operations including insert, search, delete and so on. Thus a search tree can be used both as a dictionary and as a priority queue. Binary search tree is one of fundamental search trees. The keys in a binary search tree are always stored in such a way as to satisfy the following binary search tree property: * Let $x$ be a node in a binary search tree. If $y$ is a node in the left subtree of $x$, then $y.key \leq x.key$. If $y$ is a node in the right subtree of $x$, then $x.key \leq y.key$. The following figure shows an example of the binary search tree. <image> For example, keys of nodes which belong to the left sub-tree of the node containing 80 are less than or equal to 80, and keys of nodes which belong to the right sub-tree are more than or equal to 80. The binary search tree property allows us to print out all the keys in the tree in sorted order by an inorder tree walk. A binary search tree should be implemented in such a way that the binary search tree property continues to hold after modifications by insertions and deletions. A binary search tree can be represented by a linked data structure in which each node is an object. In addition to a key field and satellite data, each node contains fields left, right, and p that point to the nodes corresponding to its left child, its right child, and its parent, respectively. To insert a new value $v$ into a binary search tree $T$, we can use the procedure insert as shown in the following pseudo code. The insert procedure is passed a node $z$ for which $z.key = v$, $z.left = NIL$, and $z.right = NIL$. The procedure modifies $T$ and some of the fields of $z$ in such a way that $z$ is inserted into an appropriate position in the tree. 1 insert(T, z) 2 y = NIL // parent of x 3 x = 'the root of T' 4 while x ≠ NIL 5 y = x // set the parent 6 if z.key < x.key 7 x = x.left // move to the left child 8 else 9 x = x.right // move to the right child 10 z.p = y 11 12 if y == NIL // T is empty 13 'the root of T' = z 14 else if z.key < y.key 15 y.left = z // z is the left child of y 16 else 17 y.right = z // z is the right child of y Write a program which performs the following operations to a binary search tree $T$. * insert $k$: Insert a node containing $k$ as key into $T$. * print: Print the keys of the binary search tree by inorder tree walk and preorder tree walk respectively. You should use the above pseudo code to implement the insert operation. $T$ is empty at the initial state. Constraints * The number of operations $\leq 500,000$ * The number of print operations $\leq 10$. * $-2,000,000,000 \leq key \leq 2,000,000,000$ * The height of the binary tree does not exceed 100 if you employ the above pseudo code. * The keys in the binary search tree are all different. Input In the first line, the number of operations $m$ is given. In the following $m$ lines, operations represented by insert $k$ or print are given. Output For each print operation, print a list of keys obtained by inorder tree walk and preorder tree walk in a line respectively. Put a space character before each key. Example Input 8 insert 30 insert 88 insert 12 insert 1 insert 20 insert 17 insert 25 print Output 1 12 17 20 25 30 88 30 12 1 20 17 25 88
instruction
0
56,379
13
112,758
"Correct Solution: ``` # coding=utf-8 class Tree(): def __init__(self): self.root = None def insert(self, key): node = Node(key) flag = False if self.root == None: self.root = node else: search_node = self.root while search_node: final_node = search_node if final_node.key < key: search_node = final_node.right flag = 'right' else: search_node = final_node.left flag = 'left' node.parent = final_node if flag == 'right': final_node.right = node elif flag == 'left': final_node.left = node def print_tree(self): prewalked = self.root.prewalk() inwalked = self.root.inwalk() print(' ', end = '') print(*inwalked) print(' ', end = '') print(*prewalked) class Node(): def __init__(self, key): self.key = key self.parent = None self.left = None self.right = None def prewalk(self): result = [] result += [self.key] # ??¢?´¢????????? # if self.left: result += self.left.prewalk() if self.right: result += self.right.prewalk() #print("self.key:", self.key, result) #debugger return result def inwalk(self): result = [] if self.left: result += self.left.inwalk() result += [self.key] # ??¢?´¢????????? # if self.right: result += self.right.inwalk() #print("self.key:", self.key, result) #debugger return result n = int(input()) tree = Tree() for _ in range(n): order, *key = input().split() if order == 'insert': tree.insert(int(key[0])) else: tree.print_tree() ```
output
1
56,379
13
112,759
Provide a correct Python 3 solution for this coding contest problem. Search trees are data structures that support dynamic set operations including insert, search, delete and so on. Thus a search tree can be used both as a dictionary and as a priority queue. Binary search tree is one of fundamental search trees. The keys in a binary search tree are always stored in such a way as to satisfy the following binary search tree property: * Let $x$ be a node in a binary search tree. If $y$ is a node in the left subtree of $x$, then $y.key \leq x.key$. If $y$ is a node in the right subtree of $x$, then $x.key \leq y.key$. The following figure shows an example of the binary search tree. <image> For example, keys of nodes which belong to the left sub-tree of the node containing 80 are less than or equal to 80, and keys of nodes which belong to the right sub-tree are more than or equal to 80. The binary search tree property allows us to print out all the keys in the tree in sorted order by an inorder tree walk. A binary search tree should be implemented in such a way that the binary search tree property continues to hold after modifications by insertions and deletions. A binary search tree can be represented by a linked data structure in which each node is an object. In addition to a key field and satellite data, each node contains fields left, right, and p that point to the nodes corresponding to its left child, its right child, and its parent, respectively. To insert a new value $v$ into a binary search tree $T$, we can use the procedure insert as shown in the following pseudo code. The insert procedure is passed a node $z$ for which $z.key = v$, $z.left = NIL$, and $z.right = NIL$. The procedure modifies $T$ and some of the fields of $z$ in such a way that $z$ is inserted into an appropriate position in the tree. 1 insert(T, z) 2 y = NIL // parent of x 3 x = 'the root of T' 4 while x ≠ NIL 5 y = x // set the parent 6 if z.key < x.key 7 x = x.left // move to the left child 8 else 9 x = x.right // move to the right child 10 z.p = y 11 12 if y == NIL // T is empty 13 'the root of T' = z 14 else if z.key < y.key 15 y.left = z // z is the left child of y 16 else 17 y.right = z // z is the right child of y Write a program which performs the following operations to a binary search tree $T$. * insert $k$: Insert a node containing $k$ as key into $T$. * print: Print the keys of the binary search tree by inorder tree walk and preorder tree walk respectively. You should use the above pseudo code to implement the insert operation. $T$ is empty at the initial state. Constraints * The number of operations $\leq 500,000$ * The number of print operations $\leq 10$. * $-2,000,000,000 \leq key \leq 2,000,000,000$ * The height of the binary tree does not exceed 100 if you employ the above pseudo code. * The keys in the binary search tree are all different. Input In the first line, the number of operations $m$ is given. In the following $m$ lines, operations represented by insert $k$ or print are given. Output For each print operation, print a list of keys obtained by inorder tree walk and preorder tree walk in a line respectively. Put a space character before each key. Example Input 8 insert 30 insert 88 insert 12 insert 1 insert 20 insert 17 insert 25 print Output 1 12 17 20 25 30 88 30 12 1 20 17 25 88
instruction
0
56,380
13
112,760
"Correct Solution: ``` import sys class Node: __slots__ = ['key', 'left', 'right'] def __init__(self, key): self.key = key self.left = self.right = None root = None def insert(key): global root x, y = root, None while x is not None: x, y = x.left if key < x.key else x.right, x if y is None: root = Node(key) elif key < y.key: y.left = Node(key) else: y.right = Node(key) def inorder(node): return inorder(node.left) + f' {node.key}' + inorder(node.right) if node else '' def preorder(node): return f' {node.key}' + preorder(node.left) + preorder(node.right) if node else '' input() for e in sys.stdin: if e[0] == 'i': insert(int(e[7:])) else: print(inorder(root)); print(preorder(root)) ```
output
1
56,380
13
112,761
Provide a correct Python 3 solution for this coding contest problem. Search trees are data structures that support dynamic set operations including insert, search, delete and so on. Thus a search tree can be used both as a dictionary and as a priority queue. Binary search tree is one of fundamental search trees. The keys in a binary search tree are always stored in such a way as to satisfy the following binary search tree property: * Let $x$ be a node in a binary search tree. If $y$ is a node in the left subtree of $x$, then $y.key \leq x.key$. If $y$ is a node in the right subtree of $x$, then $x.key \leq y.key$. The following figure shows an example of the binary search tree. <image> For example, keys of nodes which belong to the left sub-tree of the node containing 80 are less than or equal to 80, and keys of nodes which belong to the right sub-tree are more than or equal to 80. The binary search tree property allows us to print out all the keys in the tree in sorted order by an inorder tree walk. A binary search tree should be implemented in such a way that the binary search tree property continues to hold after modifications by insertions and deletions. A binary search tree can be represented by a linked data structure in which each node is an object. In addition to a key field and satellite data, each node contains fields left, right, and p that point to the nodes corresponding to its left child, its right child, and its parent, respectively. To insert a new value $v$ into a binary search tree $T$, we can use the procedure insert as shown in the following pseudo code. The insert procedure is passed a node $z$ for which $z.key = v$, $z.left = NIL$, and $z.right = NIL$. The procedure modifies $T$ and some of the fields of $z$ in such a way that $z$ is inserted into an appropriate position in the tree. 1 insert(T, z) 2 y = NIL // parent of x 3 x = 'the root of T' 4 while x ≠ NIL 5 y = x // set the parent 6 if z.key < x.key 7 x = x.left // move to the left child 8 else 9 x = x.right // move to the right child 10 z.p = y 11 12 if y == NIL // T is empty 13 'the root of T' = z 14 else if z.key < y.key 15 y.left = z // z is the left child of y 16 else 17 y.right = z // z is the right child of y Write a program which performs the following operations to a binary search tree $T$. * insert $k$: Insert a node containing $k$ as key into $T$. * print: Print the keys of the binary search tree by inorder tree walk and preorder tree walk respectively. You should use the above pseudo code to implement the insert operation. $T$ is empty at the initial state. Constraints * The number of operations $\leq 500,000$ * The number of print operations $\leq 10$. * $-2,000,000,000 \leq key \leq 2,000,000,000$ * The height of the binary tree does not exceed 100 if you employ the above pseudo code. * The keys in the binary search tree are all different. Input In the first line, the number of operations $m$ is given. In the following $m$ lines, operations represented by insert $k$ or print are given. Output For each print operation, print a list of keys obtained by inorder tree walk and preorder tree walk in a line respectively. Put a space character before each key. Example Input 8 insert 30 insert 88 insert 12 insert 1 insert 20 insert 17 insert 25 print Output 1 12 17 20 25 30 88 30 12 1 20 17 25 88
instruction
0
56,381
13
112,762
"Correct Solution: ``` class Node: def __init__(self, key, parent=None, left=None, right=None): self.key = key self.parent = parent self.left = left self.right = right class Tree: root = None preorder_list = [] inorder_list = [] def __init__(self): pass def insert(self, node): y = None x = self.root while x is not None: y = x if node.key < x.key: x = x.left else: x = x.right node.parent = y if y == None: self.root = node elif node.key < y.key: y.left = node else: y.right = node def display(self): #print(self.root, self.root.key, self.root.parent, self.root.left, self.root.right) self.inorder(self.root) self.preorder(self.root) print(' '+' '.join(map(str, self.inorder_list))) print(' '+' '.join(map(str, self.preorder_list))) pass def preorder(self, node): if node == None: return self.preorder_list.append(node.key) if node.left is not None: self.preorder(node.left) if node.right is not None: self.preorder(node.right) def inorder(self, node): if node == None: return if node.left is not None: self.inorder(node.left) self.inorder_list.append(node.key) if node.right is not None: self.inorder(node.right) n = int(input()) command_list = [list(input().split()) for _ in range(n)] tree = Tree() for command in command_list: if command[0] == 'insert': node = Node(int(command[1])) tree.insert(node) #print(node, node.key, node.parent, node.left, node.right) if command[0] == 'print': tree.display() tree.preorder_list = [] tree.inorder_list = [] ```
output
1
56,381
13
112,763
Provide a correct Python 3 solution for this coding contest problem. Search trees are data structures that support dynamic set operations including insert, search, delete and so on. Thus a search tree can be used both as a dictionary and as a priority queue. Binary search tree is one of fundamental search trees. The keys in a binary search tree are always stored in such a way as to satisfy the following binary search tree property: * Let $x$ be a node in a binary search tree. If $y$ is a node in the left subtree of $x$, then $y.key \leq x.key$. If $y$ is a node in the right subtree of $x$, then $x.key \leq y.key$. The following figure shows an example of the binary search tree. <image> For example, keys of nodes which belong to the left sub-tree of the node containing 80 are less than or equal to 80, and keys of nodes which belong to the right sub-tree are more than or equal to 80. The binary search tree property allows us to print out all the keys in the tree in sorted order by an inorder tree walk. A binary search tree should be implemented in such a way that the binary search tree property continues to hold after modifications by insertions and deletions. A binary search tree can be represented by a linked data structure in which each node is an object. In addition to a key field and satellite data, each node contains fields left, right, and p that point to the nodes corresponding to its left child, its right child, and its parent, respectively. To insert a new value $v$ into a binary search tree $T$, we can use the procedure insert as shown in the following pseudo code. The insert procedure is passed a node $z$ for which $z.key = v$, $z.left = NIL$, and $z.right = NIL$. The procedure modifies $T$ and some of the fields of $z$ in such a way that $z$ is inserted into an appropriate position in the tree. 1 insert(T, z) 2 y = NIL // parent of x 3 x = 'the root of T' 4 while x ≠ NIL 5 y = x // set the parent 6 if z.key < x.key 7 x = x.left // move to the left child 8 else 9 x = x.right // move to the right child 10 z.p = y 11 12 if y == NIL // T is empty 13 'the root of T' = z 14 else if z.key < y.key 15 y.left = z // z is the left child of y 16 else 17 y.right = z // z is the right child of y Write a program which performs the following operations to a binary search tree $T$. * insert $k$: Insert a node containing $k$ as key into $T$. * print: Print the keys of the binary search tree by inorder tree walk and preorder tree walk respectively. You should use the above pseudo code to implement the insert operation. $T$ is empty at the initial state. Constraints * The number of operations $\leq 500,000$ * The number of print operations $\leq 10$. * $-2,000,000,000 \leq key \leq 2,000,000,000$ * The height of the binary tree does not exceed 100 if you employ the above pseudo code. * The keys in the binary search tree are all different. Input In the first line, the number of operations $m$ is given. In the following $m$ lines, operations represented by insert $k$ or print are given. Output For each print operation, print a list of keys obtained by inorder tree walk and preorder tree walk in a line respectively. Put a space character before each key. Example Input 8 insert 30 insert 88 insert 12 insert 1 insert 20 insert 17 insert 25 print Output 1 12 17 20 25 30 88 30 12 1 20 17 25 88
instruction
0
56,382
13
112,764
"Correct Solution: ``` n = int(input()) class Node: def __init__(self): self.key = -1 self.parent_id = -1 self.left_id = -1 self.right_id = -1 def insert(nodes,z): y = -1 root_id = -1 for i in range(len(nodes)): if nodes[i].parent_id == -1: root_id = i break x = root_id while x != -1: y = x if z.key < nodes[x].key: x = nodes[x].left_id else: x = nodes[x].right_id z.parent_id = y nodes.append(z) z_id = len(nodes) - 1 if y == -1: pass elif z.key < nodes[y].key: nodes[y].left_id = z_id else: nodes[y].right_id = z_id def pre(node_id): pre_list.append(nodes[node_id].key) left = nodes[node_id].left_id right = nodes[node_id].right_id if left != -1: pre(left) if right != -1: pre(right) def Ino(node_id): if nodes[node_id].left_id != -1 : Ino(nodes[node_id].left_id) ino_list.append(nodes[node_id].key) if nodes[node_id].right_id != -1: Ino(nodes[node_id].right_id) nodes = [] for i in range(n): cmd = input() op = cmd[0] if op == "i": z = Node() number = int(cmd[7:]) z.key = number insert(nodes,z) if op =="p": pre_list = [] ino_list = [] for i in range(len(nodes)): if nodes[i].parent_id == -1: Ino(i) pre(i) break pre_list = list(map(str, pre_list)) ino_list = list(map(str, ino_list)) print(" ", end="") print(' '.join(ino_list)) print(" ", end="") print(' '.join(pre_list)) ```
output
1
56,382
13
112,765
Provide a correct Python 3 solution for this coding contest problem. Search trees are data structures that support dynamic set operations including insert, search, delete and so on. Thus a search tree can be used both as a dictionary and as a priority queue. Binary search tree is one of fundamental search trees. The keys in a binary search tree are always stored in such a way as to satisfy the following binary search tree property: * Let $x$ be a node in a binary search tree. If $y$ is a node in the left subtree of $x$, then $y.key \leq x.key$. If $y$ is a node in the right subtree of $x$, then $x.key \leq y.key$. The following figure shows an example of the binary search tree. <image> For example, keys of nodes which belong to the left sub-tree of the node containing 80 are less than or equal to 80, and keys of nodes which belong to the right sub-tree are more than or equal to 80. The binary search tree property allows us to print out all the keys in the tree in sorted order by an inorder tree walk. A binary search tree should be implemented in such a way that the binary search tree property continues to hold after modifications by insertions and deletions. A binary search tree can be represented by a linked data structure in which each node is an object. In addition to a key field and satellite data, each node contains fields left, right, and p that point to the nodes corresponding to its left child, its right child, and its parent, respectively. To insert a new value $v$ into a binary search tree $T$, we can use the procedure insert as shown in the following pseudo code. The insert procedure is passed a node $z$ for which $z.key = v$, $z.left = NIL$, and $z.right = NIL$. The procedure modifies $T$ and some of the fields of $z$ in such a way that $z$ is inserted into an appropriate position in the tree. 1 insert(T, z) 2 y = NIL // parent of x 3 x = 'the root of T' 4 while x ≠ NIL 5 y = x // set the parent 6 if z.key < x.key 7 x = x.left // move to the left child 8 else 9 x = x.right // move to the right child 10 z.p = y 11 12 if y == NIL // T is empty 13 'the root of T' = z 14 else if z.key < y.key 15 y.left = z // z is the left child of y 16 else 17 y.right = z // z is the right child of y Write a program which performs the following operations to a binary search tree $T$. * insert $k$: Insert a node containing $k$ as key into $T$. * print: Print the keys of the binary search tree by inorder tree walk and preorder tree walk respectively. You should use the above pseudo code to implement the insert operation. $T$ is empty at the initial state. Constraints * The number of operations $\leq 500,000$ * The number of print operations $\leq 10$. * $-2,000,000,000 \leq key \leq 2,000,000,000$ * The height of the binary tree does not exceed 100 if you employ the above pseudo code. * The keys in the binary search tree are all different. Input In the first line, the number of operations $m$ is given. In the following $m$ lines, operations represented by insert $k$ or print are given. Output For each print operation, print a list of keys obtained by inorder tree walk and preorder tree walk in a line respectively. Put a space character before each key. Example Input 8 insert 30 insert 88 insert 12 insert 1 insert 20 insert 17 insert 25 print Output 1 12 17 20 25 30 88 30 12 1 20 17 25 88
instruction
0
56,383
13
112,766
"Correct Solution: ``` import sys input = sys.stdin.readline print = sys.stdout.write class Node: __slots__ = ["data", "left", "right"] def __init__(self, data): self.data = data self.left = None self.right = None class BinarySearchTree: __slots__ = ["root"] def __init__(self): self.root = None def insert(self, data): parent = self.root if parent is None: self.root = Node(data) return while parent: parent_old = parent parent = parent.left if data < parent.data else parent.right if data < parent_old.data: parent_old.left = Node(data) else: parent_old.right = Node(data) def print_preorder(node): print(" {}".format(node.data)) if node.left: print_preorder(node.left) if node.right: print_preorder(node.right) def print_inorder(node): if node.left: print_inorder(node.left) print(" {}".format(node.data)) if node.right: print_inorder(node.right) if __name__ == "__main__": n = int(input()) binary_search_tree = BinarySearchTree() for _ in range(n): operation, *num = input().split() if num: binary_search_tree.insert(int(num[0])) elif binary_search_tree.root is not None: print_inorder(binary_search_tree.root) print("\n") print_preorder(binary_search_tree.root) print("\n") ```
output
1
56,383
13
112,767
Provide a correct Python 3 solution for this coding contest problem. Search trees are data structures that support dynamic set operations including insert, search, delete and so on. Thus a search tree can be used both as a dictionary and as a priority queue. Binary search tree is one of fundamental search trees. The keys in a binary search tree are always stored in such a way as to satisfy the following binary search tree property: * Let $x$ be a node in a binary search tree. If $y$ is a node in the left subtree of $x$, then $y.key \leq x.key$. If $y$ is a node in the right subtree of $x$, then $x.key \leq y.key$. The following figure shows an example of the binary search tree. <image> For example, keys of nodes which belong to the left sub-tree of the node containing 80 are less than or equal to 80, and keys of nodes which belong to the right sub-tree are more than or equal to 80. The binary search tree property allows us to print out all the keys in the tree in sorted order by an inorder tree walk. A binary search tree should be implemented in such a way that the binary search tree property continues to hold after modifications by insertions and deletions. A binary search tree can be represented by a linked data structure in which each node is an object. In addition to a key field and satellite data, each node contains fields left, right, and p that point to the nodes corresponding to its left child, its right child, and its parent, respectively. To insert a new value $v$ into a binary search tree $T$, we can use the procedure insert as shown in the following pseudo code. The insert procedure is passed a node $z$ for which $z.key = v$, $z.left = NIL$, and $z.right = NIL$. The procedure modifies $T$ and some of the fields of $z$ in such a way that $z$ is inserted into an appropriate position in the tree. 1 insert(T, z) 2 y = NIL // parent of x 3 x = 'the root of T' 4 while x ≠ NIL 5 y = x // set the parent 6 if z.key < x.key 7 x = x.left // move to the left child 8 else 9 x = x.right // move to the right child 10 z.p = y 11 12 if y == NIL // T is empty 13 'the root of T' = z 14 else if z.key < y.key 15 y.left = z // z is the left child of y 16 else 17 y.right = z // z is the right child of y Write a program which performs the following operations to a binary search tree $T$. * insert $k$: Insert a node containing $k$ as key into $T$. * print: Print the keys of the binary search tree by inorder tree walk and preorder tree walk respectively. You should use the above pseudo code to implement the insert operation. $T$ is empty at the initial state. Constraints * The number of operations $\leq 500,000$ * The number of print operations $\leq 10$. * $-2,000,000,000 \leq key \leq 2,000,000,000$ * The height of the binary tree does not exceed 100 if you employ the above pseudo code. * The keys in the binary search tree are all different. Input In the first line, the number of operations $m$ is given. In the following $m$ lines, operations represented by insert $k$ or print are given. Output For each print operation, print a list of keys obtained by inorder tree walk and preorder tree walk in a line respectively. Put a space character before each key. Example Input 8 insert 30 insert 88 insert 12 insert 1 insert 20 insert 17 insert 25 print Output 1 12 17 20 25 30 88 30 12 1 20 17 25 88
instruction
0
56,384
13
112,768
"Correct Solution: ``` class BinarySearchTree: root = None def insert(self, k): y = None x = self.root z = Node(k) while x: y = x if z.k < x.k: x = x.l else: x = x.r z.p = y if y == None: self.root = z else: if z.k < y.k: y.l = z else: y.r = z def preParse(self, u): if u == None: return print("", str(u.k), end = "") self.preParse(u.l) self.preParse(u.r) def inParse(self, u): if u == None: return self.inParse(u.l) print("", str(u.k), end = "") self.inParse(u.r) class Node: def __init__(self, k): self.k = k self.p = None self.l = None self.r = None if __name__ == '__main__': n = int(input().rstrip()) x = BinarySearchTree() for i in range(n): com = input().rstrip() if com.startswith("insert"): k = int(com.split(" ")[1]) x.insert(k) else: x.inParse(x.root) print() x.preParse(x.root) print() ```
output
1
56,384
13
112,769
Provide a correct Python 3 solution for this coding contest problem. Search trees are data structures that support dynamic set operations including insert, search, delete and so on. Thus a search tree can be used both as a dictionary and as a priority queue. Binary search tree is one of fundamental search trees. The keys in a binary search tree are always stored in such a way as to satisfy the following binary search tree property: * Let $x$ be a node in a binary search tree. If $y$ is a node in the left subtree of $x$, then $y.key \leq x.key$. If $y$ is a node in the right subtree of $x$, then $x.key \leq y.key$. The following figure shows an example of the binary search tree. <image> For example, keys of nodes which belong to the left sub-tree of the node containing 80 are less than or equal to 80, and keys of nodes which belong to the right sub-tree are more than or equal to 80. The binary search tree property allows us to print out all the keys in the tree in sorted order by an inorder tree walk. A binary search tree should be implemented in such a way that the binary search tree property continues to hold after modifications by insertions and deletions. A binary search tree can be represented by a linked data structure in which each node is an object. In addition to a key field and satellite data, each node contains fields left, right, and p that point to the nodes corresponding to its left child, its right child, and its parent, respectively. To insert a new value $v$ into a binary search tree $T$, we can use the procedure insert as shown in the following pseudo code. The insert procedure is passed a node $z$ for which $z.key = v$, $z.left = NIL$, and $z.right = NIL$. The procedure modifies $T$ and some of the fields of $z$ in such a way that $z$ is inserted into an appropriate position in the tree. 1 insert(T, z) 2 y = NIL // parent of x 3 x = 'the root of T' 4 while x ≠ NIL 5 y = x // set the parent 6 if z.key < x.key 7 x = x.left // move to the left child 8 else 9 x = x.right // move to the right child 10 z.p = y 11 12 if y == NIL // T is empty 13 'the root of T' = z 14 else if z.key < y.key 15 y.left = z // z is the left child of y 16 else 17 y.right = z // z is the right child of y Write a program which performs the following operations to a binary search tree $T$. * insert $k$: Insert a node containing $k$ as key into $T$. * print: Print the keys of the binary search tree by inorder tree walk and preorder tree walk respectively. You should use the above pseudo code to implement the insert operation. $T$ is empty at the initial state. Constraints * The number of operations $\leq 500,000$ * The number of print operations $\leq 10$. * $-2,000,000,000 \leq key \leq 2,000,000,000$ * The height of the binary tree does not exceed 100 if you employ the above pseudo code. * The keys in the binary search tree are all different. Input In the first line, the number of operations $m$ is given. In the following $m$ lines, operations represented by insert $k$ or print are given. Output For each print operation, print a list of keys obtained by inorder tree walk and preorder tree walk in a line respectively. Put a space character before each key. Example Input 8 insert 30 insert 88 insert 12 insert 1 insert 20 insert 17 insert 25 print Output 1 12 17 20 25 30 88 30 12 1 20 17 25 88
instruction
0
56,385
13
112,770
"Correct Solution: ``` """ 二分探索木を構成する """ import copy class Node: def __init__(self, node_id, parent=None, left=None, right=None): self.node_id = node_id self.parent = parent self.left = left self.right = right class Tree: def insert_root_node(self, new_id): global root_node #途中でインスタンス化すると水の泡なんですよ root_node = Node(new_id) def insert_node(self, root_id, new_id): #new_idは追加するノード compare_node = root_node #はじめはrootから比較スタート new_node = Node(new_id) #インスタンス化 while compare_node != None: #compare_nodeが存在するとき #この下の一行は最重要アイディア #親の可能性がある時,とりあえず代入して情報を記録しておく new_node.parent = compare_node #右か左か if compare_node.node_id < new_id: compare_node = compare_node.right else: compare_node = compare_node.left #compare_node == Noneの時,上の2つの分岐のどっちからきたかわからない #そのため,親と比較し直す必要がある if new_node.parent.node_id < new_id: new_node.parent.right = Node(new_id) else: new_node.parent.left = Node(new_id) def inParse(tmp_node): if not tmp_node: return inParse(tmp_node.left) print(' '+str(tmp_node.node_id), end='') inParse(tmp_node.right) def preParse(tmp_node): if not tmp_node: return print(' '+str(tmp_node.node_id), end='') preParse(tmp_node.left) preParse(tmp_node.right) tree = Tree() n = int(input()) root_id = 0 root_node = None for i in range(n): order = input().split() if root_node == None: #何も入ってない時 root_id = int(order[1]) tree.insert_root_node(int(order[1])) elif order[0][0] == 'i': new_id = int(order[1]) tree.insert_node(root_id, new_id) elif order[0][0] == 'p': node = copy.copy(root_node) inParse(node) print() node = copy.copy(root_node) preParse(node) print() ```
output
1
56,385
13
112,771
Provide a correct Python 3 solution for this coding contest problem. Search trees are data structures that support dynamic set operations including insert, search, delete and so on. Thus a search tree can be used both as a dictionary and as a priority queue. Binary search tree is one of fundamental search trees. The keys in a binary search tree are always stored in such a way as to satisfy the following binary search tree property: * Let $x$ be a node in a binary search tree. If $y$ is a node in the left subtree of $x$, then $y.key \leq x.key$. If $y$ is a node in the right subtree of $x$, then $x.key \leq y.key$. The following figure shows an example of the binary search tree. <image> For example, keys of nodes which belong to the left sub-tree of the node containing 80 are less than or equal to 80, and keys of nodes which belong to the right sub-tree are more than or equal to 80. The binary search tree property allows us to print out all the keys in the tree in sorted order by an inorder tree walk. A binary search tree should be implemented in such a way that the binary search tree property continues to hold after modifications by insertions and deletions. A binary search tree can be represented by a linked data structure in which each node is an object. In addition to a key field and satellite data, each node contains fields left, right, and p that point to the nodes corresponding to its left child, its right child, and its parent, respectively. To insert a new value $v$ into a binary search tree $T$, we can use the procedure insert as shown in the following pseudo code. The insert procedure is passed a node $z$ for which $z.key = v$, $z.left = NIL$, and $z.right = NIL$. The procedure modifies $T$ and some of the fields of $z$ in such a way that $z$ is inserted into an appropriate position in the tree. 1 insert(T, z) 2 y = NIL // parent of x 3 x = 'the root of T' 4 while x ≠ NIL 5 y = x // set the parent 6 if z.key < x.key 7 x = x.left // move to the left child 8 else 9 x = x.right // move to the right child 10 z.p = y 11 12 if y == NIL // T is empty 13 'the root of T' = z 14 else if z.key < y.key 15 y.left = z // z is the left child of y 16 else 17 y.right = z // z is the right child of y Write a program which performs the following operations to a binary search tree $T$. * insert $k$: Insert a node containing $k$ as key into $T$. * print: Print the keys of the binary search tree by inorder tree walk and preorder tree walk respectively. You should use the above pseudo code to implement the insert operation. $T$ is empty at the initial state. Constraints * The number of operations $\leq 500,000$ * The number of print operations $\leq 10$. * $-2,000,000,000 \leq key \leq 2,000,000,000$ * The height of the binary tree does not exceed 100 if you employ the above pseudo code. * The keys in the binary search tree are all different. Input In the first line, the number of operations $m$ is given. In the following $m$ lines, operations represented by insert $k$ or print are given. Output For each print operation, print a list of keys obtained by inorder tree walk and preorder tree walk in a line respectively. Put a space character before each key. Example Input 8 insert 30 insert 88 insert 12 insert 1 insert 20 insert 17 insert 25 print Output 1 12 17 20 25 30 88 30 12 1 20 17 25 88
instruction
0
56,386
13
112,772
"Correct Solution: ``` #http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ALDS1_8_A #???????????? def insert(root, insert_node): focus_node = root parent = None while not focus_node == None: parent = focus_node if focus_node["data"] > insert_node["data"]: focus_node = focus_node["left"] else: focus_node = focus_node["right"] if parent["data"] > insert_node["data"]: parent["left"] = insert_node else: parent["right"] = insert_node def get_preorder(node): if node == None: return [] r = [] r.append(str(node["data"])) r.extend(get_preorder(node["left"])) r.extend(get_preorder(node["right"])) return r def get_inorder(node): if node == None: return [] r = [] r.extend(get_inorder(node["left"])) r.append(str(node["data"])) r.extend(get_inorder(node["right"])) return r def print_tree(root): print(" " + " ".join(get_inorder(root))) print(" " + " ".join(get_preorder(root))) def main(): n_line = int(input()) input_list = [input() for i in range(n_line)] root = {"left":None, "right": None, "data":int(input_list[0].split()[1])} for line in input_list[1:]: if line == "print": print_tree(root) else: node = {"left":None, "right": None, "data":int(line.split()[1])} insert(root, node) if __name__ == "__main__": main() ```
output
1
56,386
13
112,773
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response. Search trees are data structures that support dynamic set operations including insert, search, delete and so on. Thus a search tree can be used both as a dictionary and as a priority queue. Binary search tree is one of fundamental search trees. The keys in a binary search tree are always stored in such a way as to satisfy the following binary search tree property: * Let $x$ be a node in a binary search tree. If $y$ is a node in the left subtree of $x$, then $y.key \leq x.key$. If $y$ is a node in the right subtree of $x$, then $x.key \leq y.key$. The following figure shows an example of the binary search tree. <image> For example, keys of nodes which belong to the left sub-tree of the node containing 80 are less than or equal to 80, and keys of nodes which belong to the right sub-tree are more than or equal to 80. The binary search tree property allows us to print out all the keys in the tree in sorted order by an inorder tree walk. A binary search tree should be implemented in such a way that the binary search tree property continues to hold after modifications by insertions and deletions. A binary search tree can be represented by a linked data structure in which each node is an object. In addition to a key field and satellite data, each node contains fields left, right, and p that point to the nodes corresponding to its left child, its right child, and its parent, respectively. To insert a new value $v$ into a binary search tree $T$, we can use the procedure insert as shown in the following pseudo code. The insert procedure is passed a node $z$ for which $z.key = v$, $z.left = NIL$, and $z.right = NIL$. The procedure modifies $T$ and some of the fields of $z$ in such a way that $z$ is inserted into an appropriate position in the tree. 1 insert(T, z) 2 y = NIL // parent of x 3 x = 'the root of T' 4 while x ≠ NIL 5 y = x // set the parent 6 if z.key < x.key 7 x = x.left // move to the left child 8 else 9 x = x.right // move to the right child 10 z.p = y 11 12 if y == NIL // T is empty 13 'the root of T' = z 14 else if z.key < y.key 15 y.left = z // z is the left child of y 16 else 17 y.right = z // z is the right child of y Write a program which performs the following operations to a binary search tree $T$. * insert $k$: Insert a node containing $k$ as key into $T$. * print: Print the keys of the binary search tree by inorder tree walk and preorder tree walk respectively. You should use the above pseudo code to implement the insert operation. $T$ is empty at the initial state. Constraints * The number of operations $\leq 500,000$ * The number of print operations $\leq 10$. * $-2,000,000,000 \leq key \leq 2,000,000,000$ * The height of the binary tree does not exceed 100 if you employ the above pseudo code. * The keys in the binary search tree are all different. Input In the first line, the number of operations $m$ is given. In the following $m$ lines, operations represented by insert $k$ or print are given. Output For each print operation, print a list of keys obtained by inorder tree walk and preorder tree walk in a line respectively. Put a space character before each key. Example Input 8 insert 30 insert 88 insert 12 insert 1 insert 20 insert 17 insert 25 print Output 1 12 17 20 25 30 88 30 12 1 20 17 25 88 Submitted Solution: ``` import sys class Node: __slots__ = ['key', 'left', 'right'] def __init__(self, key): self.key = key self.left = self.right = None root = None def insert(key): global root x, y = root, None while x: y = x if key < x.key: x = x.left else: x = x.right if y is None: root = Node(key) elif key < y.key: y.left = Node(key) else: y.right = Node(key) def inorder(node): return inorder(node.left) + f' {node.key}' + inorder(node.right) if node else '' def preorder(node): return f' {node.key}' + preorder(node.left) + preorder(node.right) if node else '' n = int(input()) for e in sys.stdin: if e[0] == 'i': insert(int(e[7:])) else: print(inorder(root)) print(preorder(root)) ```
instruction
0
56,387
13
112,774
Yes
output
1
56,387
13
112,775
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response. Search trees are data structures that support dynamic set operations including insert, search, delete and so on. Thus a search tree can be used both as a dictionary and as a priority queue. Binary search tree is one of fundamental search trees. The keys in a binary search tree are always stored in such a way as to satisfy the following binary search tree property: * Let $x$ be a node in a binary search tree. If $y$ is a node in the left subtree of $x$, then $y.key \leq x.key$. If $y$ is a node in the right subtree of $x$, then $x.key \leq y.key$. The following figure shows an example of the binary search tree. <image> For example, keys of nodes which belong to the left sub-tree of the node containing 80 are less than or equal to 80, and keys of nodes which belong to the right sub-tree are more than or equal to 80. The binary search tree property allows us to print out all the keys in the tree in sorted order by an inorder tree walk. A binary search tree should be implemented in such a way that the binary search tree property continues to hold after modifications by insertions and deletions. A binary search tree can be represented by a linked data structure in which each node is an object. In addition to a key field and satellite data, each node contains fields left, right, and p that point to the nodes corresponding to its left child, its right child, and its parent, respectively. To insert a new value $v$ into a binary search tree $T$, we can use the procedure insert as shown in the following pseudo code. The insert procedure is passed a node $z$ for which $z.key = v$, $z.left = NIL$, and $z.right = NIL$. The procedure modifies $T$ and some of the fields of $z$ in such a way that $z$ is inserted into an appropriate position in the tree. 1 insert(T, z) 2 y = NIL // parent of x 3 x = 'the root of T' 4 while x ≠ NIL 5 y = x // set the parent 6 if z.key < x.key 7 x = x.left // move to the left child 8 else 9 x = x.right // move to the right child 10 z.p = y 11 12 if y == NIL // T is empty 13 'the root of T' = z 14 else if z.key < y.key 15 y.left = z // z is the left child of y 16 else 17 y.right = z // z is the right child of y Write a program which performs the following operations to a binary search tree $T$. * insert $k$: Insert a node containing $k$ as key into $T$. * print: Print the keys of the binary search tree by inorder tree walk and preorder tree walk respectively. You should use the above pseudo code to implement the insert operation. $T$ is empty at the initial state. Constraints * The number of operations $\leq 500,000$ * The number of print operations $\leq 10$. * $-2,000,000,000 \leq key \leq 2,000,000,000$ * The height of the binary tree does not exceed 100 if you employ the above pseudo code. * The keys in the binary search tree are all different. Input In the first line, the number of operations $m$ is given. In the following $m$ lines, operations represented by insert $k$ or print are given. Output For each print operation, print a list of keys obtained by inorder tree walk and preorder tree walk in a line respectively. Put a space character before each key. Example Input 8 insert 30 insert 88 insert 12 insert 1 insert 20 insert 17 insert 25 print Output 1 12 17 20 25 30 88 30 12 1 20 17 25 88 Submitted Solution: ``` import sys class Node(): def __init__(self, key): self.key = key self.left = None self.right = None self.parent = None def preorder(self): nodeList = [self.key] if self.left: nodeList += self.left.preorder() if self.right: nodeList += self.right.preorder() return nodeList def inorder(self): nodeList = [] if self.left: nodeList += self.left.inorder() nodeList += [self.key] if self.right: nodeList += self.right.inorder() return nodeList class BinaryTree(): def __init__(self): self.root = None def insert(self, key): z = Node(key) y = None x = self.root while x: y = x if z.key < x.key: x = x.left else: x = x.right z.parent = y if y is None: self.root = z elif z.key < y.key: y.left = z else: y.right = z def print(self): print(" " + " ".join(map(str, self.root.inorder()))) print(" " + " ".join(map(str, self.root.preorder()))) if __name__ == "__main__": tree = BinaryTree() n = int(sys.stdin.readline()) for inp in sys.stdin.readlines(): inp = inp.split() if inp[0] == "insert": tree.insert(int(inp[1])) else: tree.print() ```
instruction
0
56,388
13
112,776
Yes
output
1
56,388
13
112,777
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response. Search trees are data structures that support dynamic set operations including insert, search, delete and so on. Thus a search tree can be used both as a dictionary and as a priority queue. Binary search tree is one of fundamental search trees. The keys in a binary search tree are always stored in such a way as to satisfy the following binary search tree property: * Let $x$ be a node in a binary search tree. If $y$ is a node in the left subtree of $x$, then $y.key \leq x.key$. If $y$ is a node in the right subtree of $x$, then $x.key \leq y.key$. The following figure shows an example of the binary search tree. <image> For example, keys of nodes which belong to the left sub-tree of the node containing 80 are less than or equal to 80, and keys of nodes which belong to the right sub-tree are more than or equal to 80. The binary search tree property allows us to print out all the keys in the tree in sorted order by an inorder tree walk. A binary search tree should be implemented in such a way that the binary search tree property continues to hold after modifications by insertions and deletions. A binary search tree can be represented by a linked data structure in which each node is an object. In addition to a key field and satellite data, each node contains fields left, right, and p that point to the nodes corresponding to its left child, its right child, and its parent, respectively. To insert a new value $v$ into a binary search tree $T$, we can use the procedure insert as shown in the following pseudo code. The insert procedure is passed a node $z$ for which $z.key = v$, $z.left = NIL$, and $z.right = NIL$. The procedure modifies $T$ and some of the fields of $z$ in such a way that $z$ is inserted into an appropriate position in the tree. 1 insert(T, z) 2 y = NIL // parent of x 3 x = 'the root of T' 4 while x ≠ NIL 5 y = x // set the parent 6 if z.key < x.key 7 x = x.left // move to the left child 8 else 9 x = x.right // move to the right child 10 z.p = y 11 12 if y == NIL // T is empty 13 'the root of T' = z 14 else if z.key < y.key 15 y.left = z // z is the left child of y 16 else 17 y.right = z // z is the right child of y Write a program which performs the following operations to a binary search tree $T$. * insert $k$: Insert a node containing $k$ as key into $T$. * print: Print the keys of the binary search tree by inorder tree walk and preorder tree walk respectively. You should use the above pseudo code to implement the insert operation. $T$ is empty at the initial state. Constraints * The number of operations $\leq 500,000$ * The number of print operations $\leq 10$. * $-2,000,000,000 \leq key \leq 2,000,000,000$ * The height of the binary tree does not exceed 100 if you employ the above pseudo code. * The keys in the binary search tree are all different. Input In the first line, the number of operations $m$ is given. In the following $m$ lines, operations represented by insert $k$ or print are given. Output For each print operation, print a list of keys obtained by inorder tree walk and preorder tree walk in a line respectively. Put a space character before each key. Example Input 8 insert 30 insert 88 insert 12 insert 1 insert 20 insert 17 insert 25 print Output 1 12 17 20 25 30 88 30 12 1 20 17 25 88 Submitted Solution: ``` import sys class Node: def __init__(self, value, p = None, l = None, r = None): self.key = value self.p = p self.left = l self.right = r def getroot(x): if x.p != None: return getroot(x.p) return x def preorder(x, A): if x == None: return A.append(x.key) preorder(x.left, A) preorder(x.right, A) def inorder(x, A): if x == None: return inorder(x.left, A) A.append(x.key) inorder(x.right, A) def postorder(x, A): if x == None: return postorder(x.left, A) postorder(x.right, A) A.append(x.key) def ptree(root): pre = [""] ino = [""] preorder(root, pre) inorder(root, ino) print(" ".join(map(str,ino))) print(" ".join(map(str,pre))) def insert(Tree, root, z): y = None # x ?????? x = root # 'T ??????' while x != None: y = x # ???????¨???? if z.key < x.key: x = x.left # ?????????????§???? else: x = x.right # ?????????????§???? z.p = y Tree.append(z) if y == None: # T ???????????´??? return z elif z.key < y.key: y.left = z # z ??? y ????????????????????? else: y.right = z # z ??? y ????????????????????? return root def main(): """ ????????? """ num = int(input().strip()) istr = sys.stdin.read() cmds = list(istr.splitlines()) Tree = [] root = None for i in range(num): cmd = cmds[i][0] if cmd == "i": n = Node(int(cmds[i][7:])) root = insert(Tree, root, n) elif cmd == "p": ptree(root) if __name__ == '__main__': main() ```
instruction
0
56,389
13
112,778
Yes
output
1
56,389
13
112,779
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response. Search trees are data structures that support dynamic set operations including insert, search, delete and so on. Thus a search tree can be used both as a dictionary and as a priority queue. Binary search tree is one of fundamental search trees. The keys in a binary search tree are always stored in such a way as to satisfy the following binary search tree property: * Let $x$ be a node in a binary search tree. If $y$ is a node in the left subtree of $x$, then $y.key \leq x.key$. If $y$ is a node in the right subtree of $x$, then $x.key \leq y.key$. The following figure shows an example of the binary search tree. <image> For example, keys of nodes which belong to the left sub-tree of the node containing 80 are less than or equal to 80, and keys of nodes which belong to the right sub-tree are more than or equal to 80. The binary search tree property allows us to print out all the keys in the tree in sorted order by an inorder tree walk. A binary search tree should be implemented in such a way that the binary search tree property continues to hold after modifications by insertions and deletions. A binary search tree can be represented by a linked data structure in which each node is an object. In addition to a key field and satellite data, each node contains fields left, right, and p that point to the nodes corresponding to its left child, its right child, and its parent, respectively. To insert a new value $v$ into a binary search tree $T$, we can use the procedure insert as shown in the following pseudo code. The insert procedure is passed a node $z$ for which $z.key = v$, $z.left = NIL$, and $z.right = NIL$. The procedure modifies $T$ and some of the fields of $z$ in such a way that $z$ is inserted into an appropriate position in the tree. 1 insert(T, z) 2 y = NIL // parent of x 3 x = 'the root of T' 4 while x ≠ NIL 5 y = x // set the parent 6 if z.key < x.key 7 x = x.left // move to the left child 8 else 9 x = x.right // move to the right child 10 z.p = y 11 12 if y == NIL // T is empty 13 'the root of T' = z 14 else if z.key < y.key 15 y.left = z // z is the left child of y 16 else 17 y.right = z // z is the right child of y Write a program which performs the following operations to a binary search tree $T$. * insert $k$: Insert a node containing $k$ as key into $T$. * print: Print the keys of the binary search tree by inorder tree walk and preorder tree walk respectively. You should use the above pseudo code to implement the insert operation. $T$ is empty at the initial state. Constraints * The number of operations $\leq 500,000$ * The number of print operations $\leq 10$. * $-2,000,000,000 \leq key \leq 2,000,000,000$ * The height of the binary tree does not exceed 100 if you employ the above pseudo code. * The keys in the binary search tree are all different. Input In the first line, the number of operations $m$ is given. In the following $m$ lines, operations represented by insert $k$ or print are given. Output For each print operation, print a list of keys obtained by inorder tree walk and preorder tree walk in a line respectively. Put a space character before each key. Example Input 8 insert 30 insert 88 insert 12 insert 1 insert 20 insert 17 insert 25 print Output 1 12 17 20 25 30 88 30 12 1 20 17 25 88 Submitted Solution: ``` class Node: def __init__(self,key,left,right,parent): self.key = key self.left = left self.right = right self.p = parent def __repr__(self): return str(self.key) def insert(T, z): y = None x = T while x != None: y = x if z.key < x.key: x = x.left else: x = x.right z.p = y #print(x,y,z) if y == None: #print("Y==None") T = z print(T) elif z.key<y.key: #print("z.key<y.key") y.left = z else: #print("z.key<y.key") y.right = z def printPreorder(x): if x == None: return printPreorder(x.left) print(end=' ') print(x,end='') printPreorder(x.right) def printMidorder(x): if x == None: return print(end=' ') print(x,end='') printMidorder(x.left) printMidorder(x.right) def printal(x): printPreorder(x) print() printMidorder(x) print() N = int(input()) Q = input().split() T = Node(int(Q[1]),None,None,None) for i in range(N-1): Q = input().split() if Q[0] == "print": printal(T) continue insert(T,Node(int(Q[1]),None,None,None)) ```
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Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response. Search trees are data structures that support dynamic set operations including insert, search, delete and so on. Thus a search tree can be used both as a dictionary and as a priority queue. Binary search tree is one of fundamental search trees. The keys in a binary search tree are always stored in such a way as to satisfy the following binary search tree property: * Let $x$ be a node in a binary search tree. If $y$ is a node in the left subtree of $x$, then $y.key \leq x.key$. If $y$ is a node in the right subtree of $x$, then $x.key \leq y.key$. The following figure shows an example of the binary search tree. <image> For example, keys of nodes which belong to the left sub-tree of the node containing 80 are less than or equal to 80, and keys of nodes which belong to the right sub-tree are more than or equal to 80. The binary search tree property allows us to print out all the keys in the tree in sorted order by an inorder tree walk. A binary search tree should be implemented in such a way that the binary search tree property continues to hold after modifications by insertions and deletions. A binary search tree can be represented by a linked data structure in which each node is an object. In addition to a key field and satellite data, each node contains fields left, right, and p that point to the nodes corresponding to its left child, its right child, and its parent, respectively. To insert a new value $v$ into a binary search tree $T$, we can use the procedure insert as shown in the following pseudo code. The insert procedure is passed a node $z$ for which $z.key = v$, $z.left = NIL$, and $z.right = NIL$. The procedure modifies $T$ and some of the fields of $z$ in such a way that $z$ is inserted into an appropriate position in the tree. 1 insert(T, z) 2 y = NIL // parent of x 3 x = 'the root of T' 4 while x ≠ NIL 5 y = x // set the parent 6 if z.key < x.key 7 x = x.left // move to the left child 8 else 9 x = x.right // move to the right child 10 z.p = y 11 12 if y == NIL // T is empty 13 'the root of T' = z 14 else if z.key < y.key 15 y.left = z // z is the left child of y 16 else 17 y.right = z // z is the right child of y Write a program which performs the following operations to a binary search tree $T$. * insert $k$: Insert a node containing $k$ as key into $T$. * print: Print the keys of the binary search tree by inorder tree walk and preorder tree walk respectively. You should use the above pseudo code to implement the insert operation. $T$ is empty at the initial state. Constraints * The number of operations $\leq 500,000$ * The number of print operations $\leq 10$. * $-2,000,000,000 \leq key \leq 2,000,000,000$ * The height of the binary tree does not exceed 100 if you employ the above pseudo code. * The keys in the binary search tree are all different. Input In the first line, the number of operations $m$ is given. In the following $m$ lines, operations represented by insert $k$ or print are given. Output For each print operation, print a list of keys obtained by inorder tree walk and preorder tree walk in a line respectively. Put a space character before each key. Example Input 8 insert 30 insert 88 insert 12 insert 1 insert 20 insert 17 insert 25 print Output 1 12 17 20 25 30 88 30 12 1 20 17 25 88 Submitted Solution: ``` #!/usr/bin/env python3 import sys #run by python3 class Node: def __init__(self, key): self.key = key self.right = None self.left = None def insert(T, z): #z is node which you would like to insert #initialization y = None #parent of x x = T #search while(x!=None): y = x if(z.key < x.key): x = x.left else: x = x.right #insert if(y==None): T = z elif(z.key < y.key): y.left = z else: y.right = z return T def inorder_walk(node): if node.left: inorder_walk(node.left) print ('', node.key, end='') if node.right: inorder_walk(node.right) def preorder_walk(node): print ('', node.key,end='') if node.left: preorder_walk(node.left) if node.right: preorder_walk(node.right) if __name__ == '__main__': T = None num = int(sys.stdin.readline()) for _ in range(num): cmd = sys.stdin.readline() if(cmd.startswith('i')): n = Node(int(cmd[7:])) T = insert(T, n) else: inorder_walk(T) print() preorder_walk(T) print() ```
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No
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Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response. Search trees are data structures that support dynamic set operations including insert, search, delete and so on. Thus a search tree can be used both as a dictionary and as a priority queue. Binary search tree is one of fundamental search trees. The keys in a binary search tree are always stored in such a way as to satisfy the following binary search tree property: * Let $x$ be a node in a binary search tree. If $y$ is a node in the left subtree of $x$, then $y.key \leq x.key$. If $y$ is a node in the right subtree of $x$, then $x.key \leq y.key$. The following figure shows an example of the binary search tree. <image> For example, keys of nodes which belong to the left sub-tree of the node containing 80 are less than or equal to 80, and keys of nodes which belong to the right sub-tree are more than or equal to 80. The binary search tree property allows us to print out all the keys in the tree in sorted order by an inorder tree walk. A binary search tree should be implemented in such a way that the binary search tree property continues to hold after modifications by insertions and deletions. A binary search tree can be represented by a linked data structure in which each node is an object. In addition to a key field and satellite data, each node contains fields left, right, and p that point to the nodes corresponding to its left child, its right child, and its parent, respectively. To insert a new value $v$ into a binary search tree $T$, we can use the procedure insert as shown in the following pseudo code. The insert procedure is passed a node $z$ for which $z.key = v$, $z.left = NIL$, and $z.right = NIL$. The procedure modifies $T$ and some of the fields of $z$ in such a way that $z$ is inserted into an appropriate position in the tree. 1 insert(T, z) 2 y = NIL // parent of x 3 x = 'the root of T' 4 while x ≠ NIL 5 y = x // set the parent 6 if z.key < x.key 7 x = x.left // move to the left child 8 else 9 x = x.right // move to the right child 10 z.p = y 11 12 if y == NIL // T is empty 13 'the root of T' = z 14 else if z.key < y.key 15 y.left = z // z is the left child of y 16 else 17 y.right = z // z is the right child of y Write a program which performs the following operations to a binary search tree $T$. * insert $k$: Insert a node containing $k$ as key into $T$. * print: Print the keys of the binary search tree by inorder tree walk and preorder tree walk respectively. You should use the above pseudo code to implement the insert operation. $T$ is empty at the initial state. Constraints * The number of operations $\leq 500,000$ * The number of print operations $\leq 10$. * $-2,000,000,000 \leq key \leq 2,000,000,000$ * The height of the binary tree does not exceed 100 if you employ the above pseudo code. * The keys in the binary search tree are all different. Input In the first line, the number of operations $m$ is given. In the following $m$ lines, operations represented by insert $k$ or print are given. Output For each print operation, print a list of keys obtained by inorder tree walk and preorder tree walk in a line respectively. Put a space character before each key. Example Input 8 insert 30 insert 88 insert 12 insert 1 insert 20 insert 17 insert 25 print Output 1 12 17 20 25 30 88 30 12 1 20 17 25 88 Submitted Solution: ``` class NullNode(): def __init__(self): self.id = None class Node(): def __init__(self, id): self.id = id self.parent = NullNode() self.left = NullNode() self.right = NullNode() def preorder(node, out_list=[]): if node.id is not None: out_list.append(str(node.id)) out_list = preorder(node.left, out_list) out_list = preorder(node.right, out_list) return out_list def inorder(node, out_list=[]): if node.id is not None: out_list = inorder(node.left, out_list) out_list.append(str(node.id)) out_list = inorder(node.right, out_list) return out_list def insert(node, root_node): temp_node_parent = root_node.parent temp_node = root_node while temp_node.id is not None: temp_node_parent = temp_node if node.id < temp_node.id: temp_node = temp_node.left else: temp_node = temp_node.right node.parent = temp_node_parent if node.id < temp_node_parent.id: temp_node_parent.left = node else: temp_node_parent.right = node def find(id,root_node): node = root_node while node.id is not None: if id < node.id: node = node.left elif id > node.id: node = node.right else: print('yes') break else: print('no') def delete(id, root_node): # 作成中 type = '' node = root_node node_parent = NullNode() while node.id != id: node_parent = node if id < node.id: node = node.left type = 'L' else: node = node.right type = 'R' if node.right is not None: node.right.parent = node_parent elif node.left is not None: node.left.parent = node_parent else: node.parent = NullNode() if type == 'L': node_parent.left = NullNode() else: node_parent.right = NullNode() import sys n = int(input()) input_lines = sys.stdin.readlines() root_node = NullNode() for i in range(n): input_line = input_lines[i].split() command = input_line[0] if command == 'insert': id = int(input_line[1]) id_node = Node(id) if root_node.id is None: root_node = id_node else: insert(id_node, root_node) elif command == 'find': id = int(input_line[1]) find(id, root_node) elif command == 'delete': id = int(input_line[1]) delete(id, root_node) else: inorder_list = inorder(root_node, []) preorder_list = preorder(root_node, []) print(' ' + ' '.join(inorder_list)) print(' ' + ' '.join(preorder_list)) ```
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Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response. Search trees are data structures that support dynamic set operations including insert, search, delete and so on. Thus a search tree can be used both as a dictionary and as a priority queue. Binary search tree is one of fundamental search trees. The keys in a binary search tree are always stored in such a way as to satisfy the following binary search tree property: * Let $x$ be a node in a binary search tree. If $y$ is a node in the left subtree of $x$, then $y.key \leq x.key$. If $y$ is a node in the right subtree of $x$, then $x.key \leq y.key$. The following figure shows an example of the binary search tree. <image> For example, keys of nodes which belong to the left sub-tree of the node containing 80 are less than or equal to 80, and keys of nodes which belong to the right sub-tree are more than or equal to 80. The binary search tree property allows us to print out all the keys in the tree in sorted order by an inorder tree walk. A binary search tree should be implemented in such a way that the binary search tree property continues to hold after modifications by insertions and deletions. A binary search tree can be represented by a linked data structure in which each node is an object. In addition to a key field and satellite data, each node contains fields left, right, and p that point to the nodes corresponding to its left child, its right child, and its parent, respectively. To insert a new value $v$ into a binary search tree $T$, we can use the procedure insert as shown in the following pseudo code. The insert procedure is passed a node $z$ for which $z.key = v$, $z.left = NIL$, and $z.right = NIL$. The procedure modifies $T$ and some of the fields of $z$ in such a way that $z$ is inserted into an appropriate position in the tree. 1 insert(T, z) 2 y = NIL // parent of x 3 x = 'the root of T' 4 while x ≠ NIL 5 y = x // set the parent 6 if z.key < x.key 7 x = x.left // move to the left child 8 else 9 x = x.right // move to the right child 10 z.p = y 11 12 if y == NIL // T is empty 13 'the root of T' = z 14 else if z.key < y.key 15 y.left = z // z is the left child of y 16 else 17 y.right = z // z is the right child of y Write a program which performs the following operations to a binary search tree $T$. * insert $k$: Insert a node containing $k$ as key into $T$. * print: Print the keys of the binary search tree by inorder tree walk and preorder tree walk respectively. You should use the above pseudo code to implement the insert operation. $T$ is empty at the initial state. Constraints * The number of operations $\leq 500,000$ * The number of print operations $\leq 10$. * $-2,000,000,000 \leq key \leq 2,000,000,000$ * The height of the binary tree does not exceed 100 if you employ the above pseudo code. * The keys in the binary search tree are all different. Input In the first line, the number of operations $m$ is given. In the following $m$ lines, operations represented by insert $k$ or print are given. Output For each print operation, print a list of keys obtained by inorder tree walk and preorder tree walk in a line respectively. Put a space character before each key. Example Input 8 insert 30 insert 88 insert 12 insert 1 insert 20 insert 17 insert 25 print Output 1 12 17 20 25 30 88 30 12 1 20 17 25 88 Submitted Solution: ``` class Node: def __init__(self,x): self.key = x self.left = None self.right = None def insert(node, x): if node is None: return Node(x) elif x == node.key: return node elif x < node.key: node.left = insert(node.left, x) else: node.right = insert(node.right, x) return node def preorder(node): if node == None: return None l.append(node.key) preorder(node.left) preorder(node.right) return l def inorder(node): if node == None: return None inorder(node.left) l.append(node.key) inorder(node.right) return l class BinaryTree: def __init__(self): self.root = None def insert(self, x): self.root = insert(self.root, x) def output(self): print(self.root.key) print(self.root.left.key) print(self.root.right.key) l = [] tree = BinaryTree() n = int(input()) for i in range(n): order = list(map(str, input().split())) if order[0] == "insert": tree.insert(int(order[1])) if order[0] == "print": inorder(tree.root) for i in range(len(l)): if i != len(l)-1: print(l[i],end=" ") else: print(l[i]) l.clear() preorder(tree.root) for i in range(len(l)): if i != len(l)-1: print(l[i],end=" ") else: print(l[i]) exit() else: continue ```
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Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response. Search trees are data structures that support dynamic set operations including insert, search, delete and so on. Thus a search tree can be used both as a dictionary and as a priority queue. Binary search tree is one of fundamental search trees. The keys in a binary search tree are always stored in such a way as to satisfy the following binary search tree property: * Let $x$ be a node in a binary search tree. If $y$ is a node in the left subtree of $x$, then $y.key \leq x.key$. If $y$ is a node in the right subtree of $x$, then $x.key \leq y.key$. The following figure shows an example of the binary search tree. <image> For example, keys of nodes which belong to the left sub-tree of the node containing 80 are less than or equal to 80, and keys of nodes which belong to the right sub-tree are more than or equal to 80. The binary search tree property allows us to print out all the keys in the tree in sorted order by an inorder tree walk. A binary search tree should be implemented in such a way that the binary search tree property continues to hold after modifications by insertions and deletions. A binary search tree can be represented by a linked data structure in which each node is an object. In addition to a key field and satellite data, each node contains fields left, right, and p that point to the nodes corresponding to its left child, its right child, and its parent, respectively. To insert a new value $v$ into a binary search tree $T$, we can use the procedure insert as shown in the following pseudo code. The insert procedure is passed a node $z$ for which $z.key = v$, $z.left = NIL$, and $z.right = NIL$. The procedure modifies $T$ and some of the fields of $z$ in such a way that $z$ is inserted into an appropriate position in the tree. 1 insert(T, z) 2 y = NIL // parent of x 3 x = 'the root of T' 4 while x ≠ NIL 5 y = x // set the parent 6 if z.key < x.key 7 x = x.left // move to the left child 8 else 9 x = x.right // move to the right child 10 z.p = y 11 12 if y == NIL // T is empty 13 'the root of T' = z 14 else if z.key < y.key 15 y.left = z // z is the left child of y 16 else 17 y.right = z // z is the right child of y Write a program which performs the following operations to a binary search tree $T$. * insert $k$: Insert a node containing $k$ as key into $T$. * print: Print the keys of the binary search tree by inorder tree walk and preorder tree walk respectively. You should use the above pseudo code to implement the insert operation. $T$ is empty at the initial state. Constraints * The number of operations $\leq 500,000$ * The number of print operations $\leq 10$. * $-2,000,000,000 \leq key \leq 2,000,000,000$ * The height of the binary tree does not exceed 100 if you employ the above pseudo code. * The keys in the binary search tree are all different. Input In the first line, the number of operations $m$ is given. In the following $m$ lines, operations represented by insert $k$ or print are given. Output For each print operation, print a list of keys obtained by inorder tree walk and preorder tree walk in a line respectively. Put a space character before each key. Example Input 8 insert 30 insert 88 insert 12 insert 1 insert 20 insert 17 insert 25 print Output 1 12 17 20 25 30 88 30 12 1 20 17 25 88 Submitted Solution: ``` class BinaryTree: class Node: def __init__(self, key): self.key = key self.left = None self.right = None self.parent = None def __init__(self): self.root = None def insert(self, key): if self.root is None: self.root = self.Node(key) else: root = self.root temp = None while True: temp = root if key > root.key: root = root.right if root is None: temp.right = self.Node(key) break else: root = root.left if root is None: temp.left = self.Node(key) break def print_inorder(self, node): if node is not None: self.print_inorder(node.left) print(node.key, end = " ") self.print_inorder(node.right) def print_preorder(self, node): if node is not None: print(node.key, end = " ") self.print_preorder(node.left) self.print_preorder(node.right) def test_insert(self, keys): for k in keys: self.insert(k) length = int(input()) b = BinaryTree() for _ in range(length): comm = input() if comm[0] == "i": com, num = comm.split(" ") b.insert(int(num)) else: b.print_inorder(b.root) print(" ") b.print_preorder(b.root) # # b.test_insert([30,88,12,1,20,17,25]) # b.print_inorder(b.root) # print(" ") # b.print_preorder(b.root) ```
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No
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Provide tags and a correct Python 3 solution for this coding contest problem. You are given an unweighted tree with n vertices. Then n - 1 following operations are applied to the tree. A single operation consists of the following steps: 1. choose two leaves; 2. add the length of the simple path between them to the answer; 3. remove one of the chosen leaves from the tree. Initial answer (before applying operations) is 0. Obviously after n - 1 such operations the tree will consist of a single vertex. Calculate the maximal possible answer you can achieve, and construct a sequence of operations that allows you to achieve this answer! Input The first line contains one integer number n (2 ≤ n ≤ 2·105) — the number of vertices in the tree. Next n - 1 lines describe the edges of the tree in form ai, bi (1 ≤ ai, bi ≤ n, ai ≠ bi). It is guaranteed that given graph is a tree. Output In the first line print one integer number — maximal possible answer. In the next n - 1 lines print the operations in order of their applying in format ai, bi, ci, where ai, bi — pair of the leaves that are chosen in the current operation (1 ≤ ai, bi ≤ n), ci (1 ≤ ci ≤ n, ci = ai or ci = bi) — choosen leaf that is removed from the tree in the current operation. See the examples for better understanding. Examples Input 3 1 2 1 3 Output 3 2 3 3 2 1 1 Input 5 1 2 1 3 2 4 2 5 Output 9 3 5 5 4 3 3 4 1 1 4 2 2
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Tags: constructive algorithms, dfs and similar, graphs, greedy, trees Correct Solution: ``` import sys from collections import deque as dq n = int(input()) ind = 0 inp = [int(x)-1 for line in sys.stdin.readlines() for x in line.split()] coupl = [[] for _ in range(n)] for _ in range(n-1): a,b = inp[ind],inp[ind+1] ind+=2 coupl[a].append(b) coupl[b].append(a) Q = dq() found = [False]*n master = 0 found[master] = True dia1 = 0 Q.append(master) while Q: node = Q.popleft() dia1 = node for nei in coupl[node]: if not found[nei]: found[nei] = True Q.append(nei) dia2 = 0 Q.append((dia1,0)) dist1 = [0]*n found = [False]*n found[dia1] = True while Q: node,d = Q.popleft() dia2 = node dist1[node]=d for nei in coupl[node]: if not found[nei]: found[nei] = True Q.append((nei,d+1)) Q = [] Q.append((dia2,0)) dist2 = [0]*n found = [False]*n found[dia2] = True while Q: node,d = Q.pop() dist2[node]=d for nei in coupl[node]: if not found[nei]: found[nei] = True Q.append((nei,d+1)) neigs = [0]*n leaves = [] for i in range(n): if i != dia1 and i != dia2 and len(coupl[i])==1: leaves.append(i) neigs[i]=len(coupl[i]) points = 0 lista = [] while leaves: node = leaves.pop() if dist1[node]<dist2[node]: lista.append((dia2,node,node)) points += dist2[node] else: lista.append((dia1,node,node)) points += dist1[node] for nei in coupl[node]: neigs[nei]-=1 if neigs[nei]==1: leaves.append(nei) leaves.append(dia2) while leaves: node = leaves.pop() lista.append((dia1,node,node)) points += dist1[node] for nei in coupl[node]: neigs[nei]-=1 if neigs[nei]==1: leaves.append(nei) print(points) for l in lista: a,b,c = l print(a+1,b+1,c+1) ```
output
1
56,898
13
113,797
Provide tags and a correct Python 3 solution for this coding contest problem. You are given an unweighted tree with n vertices. Then n - 1 following operations are applied to the tree. A single operation consists of the following steps: 1. choose two leaves; 2. add the length of the simple path between them to the answer; 3. remove one of the chosen leaves from the tree. Initial answer (before applying operations) is 0. Obviously after n - 1 such operations the tree will consist of a single vertex. Calculate the maximal possible answer you can achieve, and construct a sequence of operations that allows you to achieve this answer! Input The first line contains one integer number n (2 ≤ n ≤ 2·105) — the number of vertices in the tree. Next n - 1 lines describe the edges of the tree in form ai, bi (1 ≤ ai, bi ≤ n, ai ≠ bi). It is guaranteed that given graph is a tree. Output In the first line print one integer number — maximal possible answer. In the next n - 1 lines print the operations in order of their applying in format ai, bi, ci, where ai, bi — pair of the leaves that are chosen in the current operation (1 ≤ ai, bi ≤ n), ci (1 ≤ ci ≤ n, ci = ai or ci = bi) — choosen leaf that is removed from the tree in the current operation. See the examples for better understanding. Examples Input 3 1 2 1 3 Output 3 2 3 3 2 1 1 Input 5 1 2 1 3 2 4 2 5 Output 9 3 5 5 4 3 3 4 1 1 4 2 2
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13
113,798
Tags: constructive algorithms, dfs and similar, graphs, greedy, trees Correct Solution: ``` import sys def main(): n = int(input()) edges = list(map(int, sys.stdin.read().split())) tree_edges = dict() for i in range(n): tree_edges[i + 1] = set() for i in range(0, len(edges) - 1, 2): tree_edges[edges[i]].add(edges[i + 1]) tree_edges[edges[i + 1]].add(edges[i]) init_distants = [-1] * (n + 1) queue = [1] init_distants[1] = 0 while queue: next_queue = [] for process in queue: for next_vertex in tree_edges[process]: if init_distants[next_vertex] == -1: init_distants[next_vertex] = init_distants[process] + 1 next_queue.append(next_vertex) queue = next_queue head = init_distants.index(max(init_distants)) distants_from_head = [-1] * (n + 1) queue = [head] distants_from_head[head] = 0 while queue: next_queue = [] for process in queue: for next_vertex in tree_edges[process]: if distants_from_head[next_vertex] == -1: distants_from_head[next_vertex] = distants_from_head[process] + 1 next_queue.append(next_vertex) queue = next_queue tail = distants_from_head.index(max(distants_from_head)) distants_from_tail = [-1] * (n + 1) queue = [tail] distants_from_tail[tail] = 0 while queue: next_queue = [] for process in queue: for next_vertex in tree_edges[process]: if distants_from_tail[next_vertex] == -1: distants_from_tail[next_vertex] = distants_from_tail[process] + 1 next_queue.append(next_vertex) queue = next_queue path_len_sum = 0 removal_history = list() process_queue = [] for vertex, adj in tree_edges.items(): if len(adj) == 1: process_queue.append(vertex) while process_queue: next_queue = [] for leaf in process_queue: if leaf == head or leaf == tail: continue if distants_from_tail[leaf] > distants_from_head[leaf]: path_len_sum += distants_from_tail[leaf] new_leaves = [] for w in tree_edges[leaf]: tree_edges[w].remove(leaf) if len(tree_edges[w]) == 1: new_leaves.append(w) next_queue.extend(new_leaves) removal_history.append("{0} {1} {0}".format(leaf, tail)) else: path_len_sum += distants_from_head[leaf] new_leaves = [] for w in tree_edges[leaf]: tree_edges[w].remove(leaf) if len(tree_edges[w]) == 1: new_leaves.append(w) next_queue.extend(new_leaves) removal_history.append("{0} {1} {0}".format(leaf, head)) process_queue = next_queue process_queue = [tail] while process_queue: leaf = process_queue[0] if leaf == head: continue path_len_sum += distants_from_head[leaf] new_leaves = [] for w in tree_edges[leaf]: tree_edges[w].remove(leaf) if len(tree_edges[w]) == 1: new_leaves.append(w) process_queue = new_leaves removal_history.append("{0} {1} {0}".format(leaf, head)) print(str(path_len_sum)) sys.stdout.write("\n".join(removal_history)) sys.stdout.write("\n") main() ```
output
1
56,899
13
113,799