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# Python3 program to find all pairs # such that a % b = k. # Utility function to find the divisors # of n and store in vector v[] import math as mt def findDivisors(n): v = [] # Vector is used to store the divisors for i in range(1, mt.floor(n**(.5)) + 1): if (n % i == 0): # If n is a square number, push # only one occurrence if (n / i == i): v.append(i) else: v.append(i) v.append(n // i) return v # Function to find pairs such that (a%b = k) def printPairs(arr, n, k): # Store all the elements in the map # to use map as hash for finding elements # in O(1) time. occ = dict() for i in range(n): occ[arr[i]] = True isPairFound = False for i in range(n): # Print all the pairs with (a, b) as # (k, numbers greater than k) as # k % (num (> k)) = k i.e. 2%4 = 2 if (occ[k] and k < arr[i]): print("(", k, ",", arr[i], ")", end = " ") isPairFound = True # Now check for the current element as 'a' # how many b exists such that a%b = k if (arr[i] >= k): # find all the divisors of (arr[i]-k) v = findDivisors(arr[i] - k) # Check for each divisor i.e. arr[i] % b = k # or not, if yes then print that pair. for j in range(len(v)): if (arr[i] % v[j] == k and arr[i] != v[j] and occ[v[j]]): print("(", arr[i], ",", v[j], ")", end = " ") isPairFound = True return isPairFound # Driver Code arr = [3, 1, 2, 5, 4] n = len(arr) k = 2 if (printPairs(arr, n, k) == False): print("No such pair exists") # This code is contributed by mohit kumar
linear
linear
# Python3 program to convert an array # in reduced form def convert(arr, n): # Create a temp array and copy contents # of arr[] to temp temp = [arr[i] for i in range (n) ] # Sort temp array temp.sort() # create a map umap = {} # One by one insert elements of sorted # temp[] and assign them values from 0 # to n-1 val = 0 for i in range (n): umap[temp[i]] = val val += 1 # Convert array by taking positions from umap for i in range (n): arr[i] = umap[arr[i]] def printArr(arr, n): for i in range(n): print(arr[i], end = " ") # Driver Code if __name__ == "__main__": arr = [10, 20, 15, 12, 11, 50] n = len(arr) print("Given Array is ") printArr(arr, n) convert(arr , n) print("\n\nConverted Array is ") printArr(arr, n) # This code is contributed by Abhishek Gupta
linear
nlogn
# Python program to return the maximum occurring character in the input string ASCII_SIZE = 256 def getMaxOccurringChar(str): # Create array to keep the count of individual characters # Initialize the count array to zero count = [0] * ASCII_SIZE # Utility variables max = -1 c = '' # Traversing through the string and maintaining the count of # each character for i in str: count[ord(i)] += 1 for i in str: if max < count[ord(i)]: max = count[ord(i)] c = i return c # Driver program to test the above function str = "sample string" print("Max occurring character is", getMaxOccurringChar(str)) # Although this program can be written in atmost 3 lines in Python # the above program has been written for a better understanding of # the reader # Shorter version of the program # import collections # str = "sample string" # print "Max occurring character is " + # collections.Counter(str).most_common(1)[0][0] # This code has been contributed by Bhavya Jain
constant
linear
# Python program to print all words that # have the same unique character set # Function to group all strings with same characters from collections import Counter def groupStrings(input): # traverse all strings one by one # dict is an empty dictionary dict={} for word in input: # sort the current string and take it's # sorted value as key # sorted return list of sorted characters # we need to join them to get key as string # Counter() method returns dictionary with frequency of # each character as value wordDict=Counter(word) # now get list of keys key = wordDict.keys() # now sort these keys key = sorted(key) # join these characters to produce key string key = ''.join(key) # now check if this key already exist in # dictionary or not # if exist then simply append current word # in mapped list on key # otherwise first assign empty list to key and # then append current word in it if key in dict.keys(): dict[key].append(word) else: dict[key]=[] dict[key].append(word) # now traverse complete dictionary and print # list of mapped strings in each key separated by , for (key,value) in dict.items(): print (','.join(dict[key])) # Driver program if __name__ == "__main__": input=['may','student','students','dog','studentssess','god','cat','act','tab','bat','flow','wolf','lambs','amy','yam','balms','looped','poodle'] groupStrings(input)
linear
linear
# Python3 program to find out the second # most repeated word # Function to find the word def secMostRepeated(seq): # Store all the words with its occurrence occ = {} for i in range(len(seq)): occ[seq[i]] = occ.get(seq[i], 0) + 1 # Find the second largest occurrence first_max = -10**8 sec_max = -10**8 for it in occ: if (occ[it] > first_max): sec_max = first_max first_max = occ[it] elif (occ[it] > sec_max and occ[it] != first_max): sec_max = occ[it] # Return with occurrence equals # to sec_max for it in occ: if (occ[it] == sec_max): return it # Driver code if __name__ == '__main__': seq = [ "ccc", "aaa", "ccc", "ddd", "aaa", "aaa" ] print(secMostRepeated(seq)) # This code is contributed by mohit kumar 29
linear
linear
from collections import defaultdict import sys # Python program to find the smallest element # with frequency exactly k. def smallestKFreq(arr, n, k): mp = defaultdict(lambda : 0) # Map is used to store the count of # elements present in the array for i in range(n): mp[arr[i]] += 1 # Traverse the map and find minimum # element with frequency k. res = sys.maxsize res1 = sys.maxsize for key,values in mp.items(): if values == k: res = min(res, key) return res if res != res1 else -1 # Driver code arr = [2, 2, 1, 3, 1] k = 2 n = len(arr) print(smallestKFreq(arr, n, k)) # This code is contributed by Shrikant13
linear
linear
# Python3 code to find number # occurring prime number of # times with frequency >= k # Function to find number # with prime occurrences def primeOccurrences(arr, k): map = {} # Insert values and their frequencies for val in arr: freq = 0 if val in map : freq = map[val] freq += 1 else : freq = 1 map[val] = freq # Traverse map and find elements # with prime frequencies and # frequency at least k for entry in map : value = map[entry] if isPrime(value) and value >= k: print(entry) # Check if the number of occurrences # are primes or not def isPrime(n): if (n > 2 and not n % 2) or n == 1: return False for i in range(3, int(n**0.5 + 1), 2): if not n % i: return False return True # Driver code arr = [ 11, 11, 11, 23, 11, 37, 37, 51, 51, 51, 51, 51 ] k = 2 primeOccurrences(arr, k) # This code is contributed by Ansu Kumari.
linear
linear
# Python3 implementation to find k numbers # with most occurrences in the given array # Function to print the k numbers with # most occurrences def pr_N_mostFrequentNumber(arr, N, K): mp = {} for i in range(N): if arr[i] in mp: mp[arr[i]] += 1 else: mp[arr[i]] = 1 a = [0] * (len(mp)) j = 0 for i in mp: a[j] = [i, mp[i]] j += 1 a = sorted(a, key=lambda x: x[0], reverse=True) a = sorted(a, key=lambda x: x[1], reverse=True) # Display the top k numbers print(K, "numbers with most occurrences are:") for i in range(K): print(a[i][0], end=" ") # Driver code if __name__ == "__main__": arr = [3, 1, 4, 4, 5, 2, 6, 1] N = 8 K = 2 # Function call pr_N_mostFrequentNumber(arr, N, K) # This code is contributed by # Shubham Singh(SHUBHAMSINGH10)
logn
nlogn
def print_N_mostFrequentNumber(arr, N, K): # HashMap to store count of the elements count = {} # Array to store the elements according # to their frequency freq = [[] for i in range(len(arr) + 1)] for n in arr: count[n] = 1 + count.get(n, 0) for n, c in count.items(): freq.append(n) res = [] # if K elements have been printed for i in range(len(freq)-1, 0, -1): for n in freq[i]: res.append(n) if len(res) == K: return res[-1::-1] # Driver's code if __name__ == "__main__": arr = [3, 1, 4, 4, 5, 2, 6, 1] N = len(arr) K = 2 # Function call print(print_N_mostFrequentNumber(arr, N, K))
linear
linear
# Python3 program to find first repeating # element in arr[] # This function prints the first repeating # element in arr[] def printFirstRepeating(arr, n): # Initialize index of first repeating element Min = -1 # Creates an empty hashset myset = dict() # Traverse the input array from right to left for i in range(n - 1, -1, -1): # If element is already in hash set, # update Min if arr[i] in myset.keys(): Min = i else: # Else add element to hash set myset[arr[i]] = 1 # Print the result if (Min != -1): print("The first repeating element is", arr[Min]) else: print("There are no repeating elements") # Driver Code arr = [10, 5, 3, 4, 3, 5, 6] n = len(arr) printFirstRepeating(arr, n) # This code is contributed by Mohit kumar 29
linear
linear
# Python3 program to find first # repeating element in arr[] # This function prints the # first repeating element in arr[] def printFirstRepeating(arr, n): # This will set k=1, if any # repeating element found k = 0 # max = maximum from (all elements & n) max = n for i in range(n): if (max < arr[i]): max = arr[i] # Array a is for storing # 1st time occurrence of element # initialized by 0 a = [0 for i in range(max + 1)] # Store 1 in array b # if element is duplicate # initialized by 0 b = [0 for i in range(max + 1)] for i in range(n): # Duplicate element found if (a[arr[i]]): b[arr[i]] = 1 k = 1 continue else: # Storing 1st occurrence of arr[i] a[arr[i]] = i+1 if (k == 0): print("No repeating element found") else: min = max + 1 for i in range(max + 1): # Trace array a & find repeating # element with min index if (a[i] and (min > (a[i])) and b[i]): min = a[i] print(arr[min-1]) # Driver code arr = [10, 5, 3, 4, 3, 5, 6] N = len(arr) printFirstRepeating(arr, N) # This code is contributed by avanitrachhadiya2155
linear
linear
# Python3 Find the sum of all non-repeated # elements in an array # Find the sum of all non-repeated elements # in an array def findSum(arr, n): # sort all elements of array arr.sort() sum = arr[0] for i in range(0,n-1): if (arr[i] != arr[i+1]): sum = sum + arr[i+1] return sum # Driver code def main(): arr= [1, 2, 3, 1, 1, 4, 5, 6] n = len(arr) print(findSum(arr, n)) if __name__ == '__main__': main() # This code is contributed by 29AjayKumar
constant
nlogn
# Python3 Find the sum of all # non- repeated elements in an array # Find the sum of all non-repeated # elements in an array def findSum(arr, n): s = set() sum = 0 # Hash to store all element # of array for i in range(n): if arr[i] not in s: s.add(arr[i]) for i in s: sum = sum + i return sum # Driver code arr = [1, 2, 3, 1, 1, 4, 5, 6] n = len(arr) print(findSum(arr, n)) # This code is contributed by Shrikant13
linear
linear
# Python program for the above approach from collections import Counter # Function to return the sum of distinct elements def sumOfElements(arr, n): # Counter function is used to # calculate frequency of elements of array freq = Counter(arr) # Converting keys of freq dictionary to list lis = list(freq.keys()) # Return sum of list return sum(lis) # Driver code if __name__ == "__main__": arr = [1, 2, 3, 1, 1, 4, 5, 6] n = len(arr) print(sumOfElements(arr, n)) # This code is contributed by vikkycirus
linear
linear
# Python3 program to find first # non-repeating element. def firstNonRepeating(arr, n): # Loop for checking each element for i in range(n): j = 0 # Checking if ith element is present in array while(j < n): if (i != j and arr[i] == arr[j]): break j += 1 # if ith element is not present in array # except at ith index then return element if (j == n): return arr[i] return -1 # Driver code arr = [9, 4, 9, 6, 7, 4] n = len(arr) print(firstNonRepeating(arr, n)) # This code is contributed by Anant Agarwal.
constant
quadratic
# Efficient Python3 program to find first # non-repeating element. from collections import defaultdict def firstNonRepeating(arr, n): mp = defaultdict(lambda: 0) # Insert all array elements in hash table for i in range(n): mp[arr[i]] += 1 # Traverse array again and return # first element with count 1. for i in range(n): if mp[arr[i]] == 1: return arr[i] return -1 # Driver Code arr = [9, 4, 9, 6, 7, 4] n = len(arr) print(firstNonRepeating(arr, n)) # This code is contributed by Shrikant13
linear
linear
# Python3 program to print k-th distinct # element in a given array # Returns k-th distinct # element in arr. def printKDistinct(arr, n, k): dist_count = 0 for i in range(n): # Check if current element is # present somewhere else. j = 0 while j < n: if (i != j and arr[j] == arr[i]): break j += 1 # If element is unique if (j == n): dist_count += 1 if (dist_count == k): return arr[i] return -1 # Driver Code ar = [1, 2, 1, 3, 4, 2] n = len(ar) k = 2 print(printKDistinct(ar, n, k)) # This code is contributed by Mohit Kumar
constant
quadratic
# Python3 program to print k-th # distinct element in a given array def printKDistinct(arr, size, KthIndex): dict = {} vect = [] for i in range(size): if(arr[i] in dict): dict[arr[i]] = dict[arr[i]] + 1 else: dict[arr[i]] = 1 for i in range(size): if(dict[arr[i]] > 1): continue else: KthIndex = KthIndex - 1 if(KthIndex == 0): return arr[i] return -1 # Driver Code arr = [1, 2, 1, 3, 4, 2] size = len(arr) print(printKDistinct(arr, size, 2)) # This code is contributed # by Akhand Pratap Singh
linear
linear
# Simple Python 3 program to find # pairs of positive and negative # values present in an array. # Print pair with negative and # positive value def printPairs(arr, n): v = [] # For each element of array. for i in range(n): # Try to find the negative value # of arr[i] from i + 1 to n for j in range(i + 1, n): # If absolute values are # equal print pair. if (abs(arr[i]) == abs(arr[j])): v.append(abs(arr[i])) # If size of vector is 0, therefore # there is no element with positive # negative value, print "0" if (len(v) == 0): return # Print the pair with negative # positive value. for i in range(len(v)): print(-v[i], "", v[i], end=" ") # Driver Code if __name__ == "__main__": arr = [4, 8, 9, -4, 1, -1, -8, -9] n = len(arr) # Function call printPairs(arr, n) # This code is contributed # by ChitraNayal
linear
quadratic
# Python3 program to find pairs of # positive and negative values present in # an array. # Print pair with negative and # positive value def printPairs(arr, n): s = set() ret = [] # For each element of array. for i in arr: if abs(i) in s: ret.append(abs(i)) else: s.add(abs(i)) ret.sort() for i in range(0, len(ret)): print(-ret[i], "", ret[i], end=" ") # Driver Code if __name__ == "__main__": arr = [4, 8, 9, -4, 1, -1, -8, -9] n = len(arr) # Function call printPairs(arr, n) # This code is contributed by RohitOberoi
linear
linear
# Python3 program to find pairs of # positive and negative values present in # an array def printPairs(arr, n): hs = set() ans = [] for i in range(n): if (arr[i] * -1) in hs: if (arr[i] < 0): print(arr[i], end=" ") print((arr[i] * -1), end=" ") else: print((arr[i] * -1), end=" ") print(arr[i], end=" ") hs.add(arr[i]) return # Driver code arr = [4, 8, 9, -4, 1, -1, -8, -9] n = len(arr) # Function call printPairs(arr, n) # This code is contributed by shinjanpatra.
linear
linear
# Python3 program to count # divisible pairs. def countDivisibles(arr, n) : res = 0 # Iterate through all pairs for i in range(0, n) : for j in range(i+1, n) : # Increment count if one divides # other if (arr[i] % arr[j] == 0 or arr[j] % arr[i] == 0) : res+=1 return res # Driver code if __name__=='__main__': a = [1, 2, 3, 9] n = len(a) print(countDivisibles(a, n) ) # this code is contributed by # Smitha Dinesh Semwal
constant
quadratic
# Python program to count divisible pairs. import math # Function to return the total count of pairs such # that arr[i]%arr[j]==0 def total_count(arr, N): count = 0 # Storing the occurrence of every element in array # in dictionary freq = {} for i in range(0, N): if arr[i] not in freq: freq[arr[i]] = 1 else: freq[arr[i]] += 1 # Iterating through every element and finding all the # divisors of that element and then checking how many # of them are present in array arr[] for i in range(0, N): for j in range(1, int(math.sqrt(arr[i]))+1): if arr[i] % j == 0: if arr[i] == j*j: # If divisors are equal, then take only # one as it will be perfect square root # of arr[i] count += freq[j] else: # Else take both j and arr[i]/j as both # will be divisors count += freq[j]+freq[arr[i]/j] # As all the elements is divisible by itself and # is counted in freq[] so reducing its count count = count-1 # returning final count return count arr = [1, 2, 3, 9] N = len(arr) print(total_count(arr, N)) # This code is contributed by lokesh (lokeshmvs21).
constant
quadratic
# Python3 implementation to find the # longest subarray with sum divisible by k # Function to find the longest # subarray with sum divisible by k def longestSubarrWthSumDivByK(arr, n, k): # unordered map 'um' implemented # as hash table um = {} # 'mod_arr[i]' stores (sum[0..i] % k) mod_arr = [0 for i in range(n)] max_len = 0 curr_sum = 0 # Traverse arr[] and build up # the array 'mod_arr[]' for i in range(n): curr_sum += arr[i] # As the sum can be negative, # taking modulo twice mod_arr[i] = ((curr_sum % k) + k) % k # If true then sum(0..i) is # divisible by k if (mod_arr[i] == 0): # Update 'max_len' max_len = i + 1 # If value 'mod_arr[i]' not present in # 'um' then store it in 'um' with index # of its first occurrence elif (mod_arr[i] not in um): um[mod_arr[i]] = i else: # If true, then update 'max_len' if (max_len < (i - um[mod_arr[i]])): max_len = i - um[mod_arr[i]] # Return the required length of longest subarray # with sum divisible by 'k' return max_len # Driver Code if __name__ == '__main__': arr = [2, 7, 6, 1, 4, 5] n = len(arr) k = 3 print("Length =", longestSubarrWthSumDivByK(arr, n, k)) # This code is contributed by Surendra_Gangwar, updated by Kshitij Dwivedi
linear
linear
# function to find the longest subarray # with sum divisible by k def longestSubarrWthSumDivByK(arr, n, k): # unordered map 'um' implemented as # hash table um = {} max_len = 0 curr_sum = 0 for i in range(n): curr_sum += arr[i] mod = ((curr_sum % k) + k) % k # if true then sum(0..i) is divisible by k if mod == 0: # update 'max_len' max_len = i + 1 # if value 'mod_arr[i]' not present in 'um' # then store it in 'um' with index of its # first occurrence elif mod in um.keys(): if max_len < (i - um[mod]): max_len = i - um[mod] else: um[mod] = i # return the required length of longest subarray with # sum divisible by 'k' return max_len arr = [2, 7, 6, 1, 4, 5] n = len(arr) k = 3 print("Length =", longestSubarrWthSumDivByK(arr, n, k)) # This code is contributed by amreshkumar3, and updated by Kshitij Dwivedi
linear
linear
# Python3 Program to find the subarray with # no pair sum divisible by K # function to find the subarray with # no pair sum divisible by k def subarrayDivisibleByK(arr, n, k) : # hash table to store the remainders # obtained on dividing by K mp = [0] * 1000 # s : starting index of the # current subarray, e : ending # index of the current subarray, maxs : # starting index of the maximum # size subarray so far, maxe : ending # index of the maximum size subarray # so far s = 0; e = 0; maxs = 0; maxe = 0; # insert the first element in the set mp[arr[0] % k] = mp[arr[0] % k] + 1; for i in range(1, n): mod = arr[i] % k # Removing starting elements of current # subarray while there is an element in # set which makes a pair with mod[i] such # that the pair sum is divisible. while (mp[k - mod] != 0 or (mod == 0 and mp[mod] != 0)) : mp[arr[s] % k] = mp[arr[s] % k] - 1 s = s + 1 # include the current element in # the current subarray the ending # index of the current subarray # increments by one mp[mod] = mp[mod] + 1 e = e + 1 # compare the size of the current # subarray with the maximum size so # far if ((e - s) > (maxe - maxs)) : maxe = e maxs = s print ("The maximum size is {} and the " " subarray is as follows" .format((maxe - maxs + 1))) for i in range(maxs, maxe + 1) : print ("{} ".format(arr[i]), end="") # Driver Code k = 3 arr = [5, 10, 15, 20, 25] n = len(arr) subarrayDivisibleByK(arr, n, k) # This code is contributed by # Manish Shaw (manishshaw1)
linear
nlogn
# Python3 program to find special numbers # in an array import math as mt # Function to find special numbers def divisibilityCheck(arr, n): # Storing all array elements in a hash # and finding maximum element in array s = dict() max_ele = -10**9 for i in range(n): s[arr[i]] = 1 # finding maximum element of array max_ele = max(max_ele, arr[i]) # traversing array element and storing # the array multiples that are present # in s in res. res = dict() for i in range(n): # Check for non-zero values only if (arr[i] != 0): # checking the factor of current element for j in range(arr[i] * 2, max_ele + 1, arr[i]): # if factor is already part of # array element then store it if (j in s.keys()): res[j] = 1 # displaying elements that are divisible # by at least one other in array for x in res: print(x, end = " ") # Driver code arr = [ 2, 3, 8, 6, 9, 10] n = len(arr) divisibilityCheck(arr, n) # This code is contributed by # Mohit Kumar 29
linear
quadratic
# Python3 program to find # three element from different # three arrays such that # a + b + c is equal to # given sum # Function to check if there # is an element from each # array such that sum of the # three elements is equal to # given sum. def findTriplet(a1, a2, a3, n1, n2, n3, sum): for i in range(0 , n1): for j in range(0 , n2): for k in range(0 , n3): if (a1[i] + a2[j] + a3[k] == sum): return True return False # Driver Code a1 = [ 1 , 2 , 3 , 4 , 5 ] a2 = [ 2 , 3 , 6 , 1 , 2 ] a3 = [ 3 , 2 , 4 , 5 , 6 ] sum = 9 n1 = len(a1) n2 = len(a2) n3 = len(a3) print("Yes") if findTriplet(a1, a2, a3, n1, n2, n3, sum) else print("No") # This code is contributed # by Smitha
constant
cubic
# Python3 program to find three element # from different three arrays such # that a + b + c is equal to # given sum # Function to check if there is # an element from each array such # that sum of the three elements is # equal to given sum. def findTriplet(a1, a2, a3, n1, n2, n3, sum): # Store elements of first # array in hash s = set() # sum last two arrays element # one by one for i in range(n1): s.add(a1[i]) for i in range(n2): for j in range(n3): # Consider current pair and # find if there is an element # in a1[] such that these three # form a required triplet if sum - a2[i] - a3[j] in s: return True return False # Driver code a1 = [1, 2, 3, 4, 5] a2 = [2, 3, 6, 1, 2] a3 = [3, 24, 5, 6] n1 = len(a1) n2 = len(a2) n3 = len(a3) sum = 9 if findTriplet(a1, a2, a3, n1, n2, n3, sum) == True: print("Yes") else: print("No") # This code is contributed by Shrikant13
linear
quadratic
# Python program for the above approach # returns the length def maxLen(arr): # initialize result max_len = 0 # pick a starting point for i in range(len(arr)): # initialize sum for every starting point curr_sum = 0 # try all subarrays starting with 'i' for j in range(i, len(arr)): curr_sum += arr[j] # if curr_sum becomes 0, then update max_len if curr_sum == 0: max_len = max(max_len, j-i + 1) return max_len # Driver's code if __name__ == "__main__": # test array arr = [15, -2, 2, -8, 1, 7, 10, 13] # Function call print ("Length of the longest 0 sum subarray is % d" % maxLen(arr))
constant
quadratic
# Python program for the above approach # Returns the maximum length def maxLen(arr): # NOTE: Dictionary in python is # implemented as Hash Maps # Create an empty hash map (dictionary) hash_map = {} # Initialize result max_len = 0 # Initialize sum of elements curr_sum = 0 # Traverse through the given array for i in range(len(arr)): # Add the current element to the sum curr_sum += arr[i] if curr_sum == 0: max_len = i + 1 # NOTE: 'in' operation in dictionary # to search key takes O(1). Look if # current sum is seen before if curr_sum in hash_map: max_len = max(max_len, i - hash_map[curr_sum]) else: # else put this sum in dictionary hash_map[curr_sum] = i return max_len # Driver's code if __name__ == "__main__": # test array arr = [15, -2, 2, -8, 1, 7, 10, 13] # Function call print("Length of the longest 0 sum subarray is % d" % maxLen(arr))
linear
linear
# Python 3 program to find length of # the longest increasing subsequence # whose adjacent element differ by 1 import sys # function that returns the length # of the longest increasing subsequence # whose adjacent element differ by 1 def longestSubsequence(a, n): # stores the index of elements mp = {i:0 for i in range(13)} # stores the length of the longest # subsequence that ends with a[i] dp = [0 for i in range(n)] maximum = -sys.maxsize - 1 # iterate for all element index = -1 for i in range(n): # if a[i]-1 is present before # i-th index if ((a[i] - 1 ) in mp): # last index of a[i]-1 lastIndex = mp[a[i] - 1] - 1 # relation dp[i] = 1 + dp[lastIndex] else: dp[i] = 1 # stores the index as 1-index as we # need to check for occurrence, hence # 0-th index will not be possible to check mp[a[i]] = i + 1 # stores the longest length if (maximum < dp[i]): maximum = dp[i] index = i # We know last element of sequence is # a[index]. We also know that length # of subsequence is "maximum". So We # print these many consecutive elements # starting from "a[index] - maximum + 1" # to a[index]. for curr in range(a[index] - maximum + 1, a[index] + 1, 1): print(curr, end = " ") # Driver Code if __name__ == '__main__': a = [3, 10, 3, 11, 4, 5, 6, 7, 8, 12] n = len(a) longestSubsequence(a, n) # This code is contributed by # Surendra_Gangwar
linear
linear
# python program to find length of the # longest increasing subsequence # whose adjacent element differ by 1 from collections import defaultdict import sys # function that returns the length of the # longest increasing subsequence # whose adjacent element differ by 1 def longestSubsequence(a, n): mp = defaultdict(lambda:0) # stores the length of the longest # subsequence that ends with a[i] dp = [0 for i in range(n)] maximum = -sys.maxsize # iterate for all element for i in range(n): # if a[i]-1 is present before i-th index if a[i] - 1 in mp: # last index of a[i]-1 lastIndex = mp[a[i] - 1] - 1 # relation dp[i] = 1 + dp[lastIndex] else: dp[i] = 1 # stores the index as 1-index as we need to # check for occurrence, hence 0-th index # will not be possible to check mp[a[i]] = i + 1 # stores the longest length maximum = max(maximum, dp[i]) return maximum # Driver Code a = [3, 10, 3, 11, 4, 5, 6, 7, 8, 12] n = len(a) print(longestSubsequence(a, n)) # This code is contributed by Shrikant13
linear
linear
# Python3 implementation to find longest # subsequence such that difference between # adjacents is one from collections import defaultdict # function to find longest subsequence such # that difference between adjacents is one def longLenSub(arr, n): # hash table to map the array element # with the length of the longest # subsequence of which it is a part of # and is the last element of that subsequence um = defaultdict(lambda:0) longLen = 0 for i in range(n): # / initialize current length # for element arr[i] as 0 len1 = 0 # if 'arr[i]-1' is in 'um' and its length # of subsequence is greater than 'len' if (arr[i - 1] in um and len1 < um[arr[i] - 1]): len1 = um[arr[i] - 1] # f 'arr[i]+1' is in 'um' and its length # of subsequence is greater than 'len' if (arr[i] + 1 in um and len1 < um[arr[i] + 1]): len1 = um[arr[i] + 1] # update arr[i] subsequence # length in 'um' um[arr[i]] = len1 + 1 # update longest length if longLen < um[arr[i]]: longLen = um[arr[i]] # required longest length # subsequence return longLen # Driver code arr = [1, 2, 3, 4, 5, 3, 2] n = len(arr) print("Longest length subsequence =", longLenSub(arr, n)) # This code is contributed by Shrikant13
linear
linear
# Python3 program to find longest # contiguous subsequence # Returns length of the longest # contiguous subsequence def findLongestConseqSubseq(arr, n): ans = 0 count = 0 # Sort the array arr.sort() v = [] v.append(arr[0]) # Insert repeated elements only # once in the vector for i in range(1, n): if (arr[i] != arr[i - 1]): v.append(arr[i]) # Find the maximum length # by traversing the array for i in range(len(v)): # Check if the current element is # equal to previous element +1 if (i > 0 and v[i] == v[i - 1] + 1): count += 1 # Reset the count else: count = 1 # Update the maximum ans = max(ans, count) return ans # Driver code arr = [1, 2, 2, 3] n = len(arr) print("Length of the Longest contiguous subsequence is", findLongestConseqSubseq(arr, n)) # This code is contributed by avanitrachhadiya2155
linear
nlogn
# Python program to find longest contiguous subsequence def findLongestConseqSubseq(arr, n): s = set() ans = 0 # Hash all the array elements for ele in arr: s.add(ele) # check each possible sequence from the start # then update optimal length for i in range(n): # if current element is the starting # element of a sequence if (arr[i]-1) not in s: # Then check for next elements in the # sequence j = arr[i] while(j in s): j += 1 # update optimal length if this length # is more ans = max(ans, j-arr[i]) return ans # Driver code if __name__ == '__main__': n = 7 arr = [1, 9, 3, 10, 4, 20, 2] print("Length of the Longest contiguous subsequence is ", findLongestConseqSubseq(arr, n)) # Contributed by: Harshit Sidhwa
linear
linear
# Python program for the above approach import bisect def findLongestConseqSubseq(arr, N): pq = [] for i in range(N): # adding element from # array to PriorityQueue bisect.insort(pq, arr[i]) # Storing the first element # of the Priority Queue # This first element is also # the smallest element prev = pq[0] pq.pop(0) # Taking a counter variable with value 1 c = 1 # Storing value of max as 1 # as there will always be # one element max = 1 while(len(pq)): # check if current peek # element minus previous # element is greater than # 1 This is done because # if it's greater than 1 # then the sequence # doesn't start or is broken here if(pq[0] - prev > 1): # Store the value of counter to 1 # As new sequence may begin c = 1 # Update the previous position with the # current peek And remove it prev = pq[0] pq.pop(0) # Check if the previous # element and peek are same elif(pq[0] - prev == 0): # Update the previous position with the # current peek And remove it prev = pq[0] pq.pop(0) # If the difference # between previous element and peek is 1 else: # Update the counter # These are consecutive elements c = c + 1 # Update the previous position # with the current peek And remove it prev = pq[0] pq.pop(0) # Check if current longest # subsequence is the greatest if(max < c): # Store the current subsequence count as # max max = c return max # Driver Code arr = [1, 9, 3, 10, 4, 20, 2] n = 7 print("Length of the Longest consecutive subsequence is {}".format( findLongestConseqSubseq(arr, n))) # This code is contributed by Pushpesh Raj
linear
nlogn
# Python3 implementation of longest # continuous increasing subsequence # Function for LIS def findLIS(A, n): hash = dict() # Initialize result LIS_size, LIS_index = 1, 0 hash[A[0]] = 1 # iterate through array and find # end index of LIS and its Size for i in range(1, n): # If the desired key is not present # in dictionary, it will throw key error, # to avoid this error this is necessary if A[i] - 1 not in hash: hash[A[i] - 1] = 0 hash[A[i]] = hash[A[i] - 1] + 1 if LIS_size < hash[A[i]]: LIS_size = hash[A[i]] LIS_index = A[i] # print LIS size print("LIS_size =", LIS_size) # print LIS after setting start element print("LIS : ", end = "") start = LIS_index - LIS_size + 1 while start <= LIS_index: print(start, end = " ") start += 1 # Driver Code if __name__ == "__main__": A = [ 2, 5, 3, 7, 4, 8, 5, 13, 6 ] n = len(A) findLIS(A, n) # This code is contributed by sanjeev2552
linear
linear
# python implementation to count subsets having # even numbers only and all are distinct #function to count the required subsets def countSubSets(arr, n): us = set() even_count = 0 # inserting even numbers in the set 'us' # single copy of each number is retained for i in range(n): if arr[i] % 2 == 0: us.add(arr[i]) # counting distinct even numbers even_count = len(us) # total count of required subsets return pow(2, even_count)- 1 # Driver program arr = [4, 2, 1, 9, 2, 6, 5, 3] n = len(arr) print("Numbers of subset=", countSubSets(arr,n)) # This code is contributed by Shrikant13
linear
linear
# Python3 program to count distinct # elements in every window of size K import math as mt # Counts distinct elements in window # of size K def countWindowDistinct(win, K): dist_count = 0 # Traverse the window for i in range(K): # Check if element arr[i] exists # in arr[0..i-1] j = 0 while j < i: if (win[i] == win[j]): break else: j += 1 if (j == i): dist_count += 1 return dist_count # Counts distinct elements in all # windows of size k def countDistinct(arr, N, K): # Traverse through every window for i in range(N - K + 1): print(countWindowDistinct(arr[i:K + i], K)) # Driver's Code if __name__=='__main__': arr = [1, 2, 1, 3, 4, 2, 3] K = 4 N = len(arr) # Function call countDistinct(arr, N, K) # This code is contributed by # Mohit kumar 29
constant
quadratic
# An efficient Python program to # count distinct elements in # every window of size K from collections import defaultdict def countDistinct(arr, K, N): # Creates an empty hashmap hm mp = defaultdict(lambda: 0) # initialize distinct element # count for current window dist_count = 0 # Traverse the first window and store count # of every element in hash map for i in range(K): if mp[arr[i]] == 0: dist_count += 1 mp[arr[i]] += 1 # Print count of first window print(dist_count) # Traverse through the remaining array for i in range(K, N): # Remove first element of previous window # If there was only one occurrence, # then reduce distinct count. if mp[arr[i - K]] == 1: dist_count -= 1 mp[arr[i - K]] -= 1 # Add new element of current window # If this element appears first time, # increment distinct element count if mp[arr[i]] == 0: dist_count += 1 mp[arr[i]] += 1 # Print count of current window print(dist_count) # Driver's code if __name__=='__main__': arr = [1, 2, 1, 3, 4, 2, 3] N = len(arr) K = 4 # Function call countDistinct(arr, K, N) # This code is contributed by Shrikant13
linear
linear
# Python3 program to find the maximum # possible sum of a window in one # array such that elements in same # window of other array are unique. # Function to return maximum sum of window # in B[] according to given constraints. def returnMaxSum(A, B, n): # Map is used to store elements # and their counts. mp = set() result = 0 # Initialize result # calculating the maximum possible # sum for each subarray containing # unique elements. curr_sum = curr_begin = 0 for i in range(0, n): # Remove all duplicate instances # of A[i] in current window. while A[i] in mp: mp.remove(A[curr_begin]) curr_sum -= B[curr_begin] curr_begin += 1 # Add current instance of A[i] # to map and to current sum. mp.add(A[i]) curr_sum += B[i] # Update result if current # sum is more. result = max(result, curr_sum) return result # Driver code if __name__ == "__main__": A = [0, 1, 2, 3, 0, 1, 4] B = [9, 8, 1, 2, 3, 4, 5] n = len(A) print(returnMaxSum(A, B, n)) # This code is contributed by Rituraj Jain
linear
linear
# python3 program to find if # there is a zero sum subarray def subArrayExists(arr, N): # traverse through array # and store prefix sums n_sum = 0 s = set() for i in range(N): n_sum += arr[i] # If prefix sum is 0 or # it is already present if n_sum == 0 or n_sum in s: return True s.add(n_sum) return False # Driver's code if __name__ == '__main__': arr = [-3, 2, 3, 1, 6] N = len(arr) # Function call if subArrayExists(arr, N) == True: print("Found a sunbarray with 0 sum") else: print("No Such sub array exits!") # This code is contributed by Shrikant13
linear
linear
# User defined pair class class Pair : first = 0 second = 0 def __init__(self, a, b) : self.first = a self.second = b class GFG : @staticmethod def findSubArrays( arr, n) : # Array to store all the start and end # indices of subarrays with 0 sum out = [] i = 0 while (i < n) : prefix = 0 j = i while (j < n) : prefix += arr[j] if (prefix == 0) : out.append(Pair(i, j)) j += 1 i += 1 return out # Function to print all subarrays with 0 sum @staticmethod def print( out) : i = 0 while (i < len(out)) : p = out[i] print("Subarray found from Index " + str(p.first) + " to " + str(p.second)) i += 1 # Driver code @staticmethod def main( args) : # Given array arr = [6, 3, -1, -3, 4, -2, 2, 4, 6, -12, -7] n = len(arr) # Function Call out = GFG.findSubArrays(arr, n) # if we didn't find any subarray with 0 sum, # then subarray doesn't exists if (len(out) == 0) : print("No subarray exists") else : GFG.print(out) if __name__=="__main__": GFG.main([]) # This code is contributed by aadityaburujwale.
constant
quadratic
# Python3 program to print all subarrays # in the array which has sum 0 # Function to get all subarrays # in the array which has sum 0 def findSubArrays(arr,n): # create a python dict hashMap = {} # create a python list # equivalent to ArrayList out = [] # tracker for sum of elements sum1 = 0 for i in range(n): # increment sum by element of array sum1 += arr[i] # if sum is 0, we found a subarray starting # from index 0 and ending at index i if sum1 == 0: out.append((0, i)) al = [] # If sum already exists in the map # there exists at-least one subarray # ending at index i with 0 sum if sum1 in hashMap: # map[sum] stores starting index # of all subarrays al = hashMap.get(sum1) for it in range(len(al)): out.append((al[it] + 1, i)) al.append(i) hashMap[sum1] = al return out # Utility function to print # all subarrays with sum 0 def printOutput(output): for i in output: print ("Subarray found from Index " + str(i[0]) + " to " + str(i[1])) # Driver Code if __name__ == '__main__': arr = [6, 3, -1, -3, 4, -2, 2, 4, 6, -12, -7] n = len(arr) out = findSubArrays(arr, n) # if we did not find any subarray with 0 sum, # then subarray does not exists if (len(out) == 0): print ("No subarray exists") else: printOutput (out) # This code is contributed by Vikas Chitturi
linear
linear
# Python3 program to print subarray # with sum as given sum # Returns true if the there is a subarray # of arr[] with sum equal to 'sum' otherwise # returns false. Also, prints the result */ def subArraySum(arr, n, sum): # Pick a starting point for i in range(n): curr_sum = 0 # try all subarrays starting with 'i' for j in range(i, n): curr_sum += arr[j] if (curr_sum == sum): print("Sum found between indexes", i, "and", j) return print("No subarray found") # Driver Code if __name__ == "__main__": arr = [15, 2, 4, 8, 9, 5, 10, 23] n = len(arr) sum = 23 # Function Call subArraySum(arr, n, sum) # This code is contributed by phasing17
constant
quadratic
# Python3 program to print subarray with sum as given sum # Function to print subarray with sum as given sum def subArraySum(arr, n, Sum): # create an empty map Map = {} # Maintains sum of elements so far curr_sum = 0 for i in range(0, n): # add current element to curr_sum curr_sum = curr_sum + arr[i] # if curr_sum is equal to target sum # we found a subarray starting from index 0 # and ending at index i if curr_sum == Sum: print("Sum found between indexes 0 to", i) return # If curr_sum - sum already exists in map # we have found a subarray with target sum if (curr_sum - Sum) in Map: print("Sum found between indexes", Map[curr_sum - Sum] + 1, "to", i) return Map[curr_sum] = i # If we reach here, then no subarray exists print("No subarray with given sum exists") # Driver code if __name__ == "__main__": arr = [10, 2, -2, -20, 10] n = len(arr) Sum = -10 # Function call subArraySum(arr, n, Sum) # This code is contributed by Rituraj Jain
linear
linear
# Python3 program to find minimum number # of insertions to make a string # palindrome import math as mt # Function will return number of # characters to be added def minInsertion(tr1): # To store string length n = len(str1) # To store number of characters # occurring odd number of times res = 0 # To store count of each # character count = [0 for i in range(26)] # To store occurrence of each # character for i in range(n): count[ord(str1[i]) - ord('a')] += 1 # To count characters with odd # occurrence for i in range(26): if (count[i] % 2 == 1): res += 1 # As one character can be odd return # res - 1 but if string is already # palindrome return 0 if (res == 0): return 0 else: return res - 1 # Driver Code str1 = "geeksforgeeks" print(minInsertion(str1)) # This code is contributed by # Mohit kumar 29
constant
linear
# Python3 implementation to find maximum # length subsequence with difference between # adjacent elements as either 0 or 1 from collections import defaultdict # Function to find maximum length subsequence with # difference between adjacent elements as either 0 or 1 def maxLenSub(arr, n): # hash table to map the array element with the # length of the longest subsequence of which it is a # part of and is the last element of that subsequence um = defaultdict(lambda:0) # to store the maximum length subsequence maxLen = 0 # traverse the array elements for i in range(0, n): # initialize current length # for element arr[i] as 0 length = 0 # if 'arr[i]-1' is in 'um' and its length of # subsequence is greater than 'len' if (arr[i]-1) in um and length < um[arr[i]-1]: length = um[arr[i]-1] # if 'arr[i]' is in 'um' and its length of # subsequence is greater than 'len' if arr[i] in um and length < um[arr[i]]: length = um[arr[i]] # if 'arr[i]+1' is in 'um' and its length of # subsequence is greater than 'len' if (arr[i]+1) in um and length < um[arr[i]+1]: length = um[arr[i]+1] # update arr[i] subsequence length in 'um' um[arr[i]] = length + 1 # update maximum length if maxLen < um[arr[i]]: maxLen = um[arr[i]] # required maximum length subsequence return maxLen # Driver program to test above if __name__ == "__main__": arr = [2, 5, 6, 3, 7, 6, 5, 8] n = len(arr) print("Maximum length subsequence =", maxLenSub(arr, n)) # This code is contributed by Rituraj Jain
linear
linear
# Python program to find maximum difference # between frequency of any two element # such that element with greater frequency # is also greater in value. from collections import defaultdict # Return the maximum difference between # frequencies of any two elements such that # element with greater frequency is also # greater in value. def maxdiff(arr, n): freq = defaultdict(lambda: 0) # Finding the frequency of each element. for i in range(n): freq[arr[i]] += 1 ans = 0 for i in range(n): for j in range(n): # finding difference such that element # having greater frequency is also # greater in value. if freq[arr[i]] > freq[arr[j]] and arr[i] > arr[j]: ans = max(ans, freq[arr[i]] - freq[arr[j]]) elif freq[arr[i]] < freq[arr[j]] and arr[i] < arr[j]: ans = max(ans, freq[arr[j]] - freq[arr[i]]) return ans arr = [3,1,3,2,3,2] n = len(arr) print(maxdiff(arr,n)) # This code is contributed by Shrikant13
linear
quadratic
# Efficient Python3 program to find maximum # difference between frequency of any two # elements such that element with greater # frequency is also greater in value. # Return the maximum difference between # frequencies of any two elements such that # element with greater frequency is also # greater in value. def maxdiff(arr, n): freq = {} dist = [0] * n # Finding the frequency of each element. j = 0 for i in range(n): if (arr[i] not in freq): dist[j] = arr[i] j += 1 freq[arr[i]] = 0 if (arr[i] in freq): freq[arr[i]] += 1 dist = dist[:j] # Sorting the distinct element dist.sort() min_freq = n + 1 # Iterate through all sorted distinct elements. # For each distinct element, maintaining the # element with minimum frequency than that # element and also finding the maximum # frequency difference ans = 0 for i in range(j): cur_freq = freq[dist[i]] ans = max(ans, cur_freq - min_freq) min_freq = min(min_freq, cur_freq) return ans # Driven Program arr = [3, 1, 3, 2, 3, 2] n = len(arr) print(maxdiff(arr, n)) # This code is contributed by SHUBHAMSINGH10
linear
nlogn
# Python3 code to find the difference # between highest nd least frequencies def findDiff(arr, n): # sort the array arr.sort() count = 0; max_count = 0; min_count = n for i in range(0, (n-1)): # checking consecutive elements if arr[i] == arr[i + 1]: count += 1 continue else: max_count = max(max_count, count) min_count = min(min_count, count) count = 0 return max_count - min_count # Driver Code arr = [ 7, 8, 4, 5, 4, 1, 1, 7, 7, 2, 5 ] n = len(arr) print (findDiff(arr, n)) # This code is contributed by Shreyanshi Arun.
constant
nlogn
# Python code to find the difference between highest # and least frequencies from collections import defaultdict def findDiff(arr,n): # Put all elements in a hash map mp = defaultdict(lambda:0) for i in range(n): mp[arr[i]]+=1 # Find counts of maximum and minimum # frequent elements max_count=0;min_count=n for key,values in mp.items(): max_count= max(max_count,values) min_count = min(min_count,values) return max_count-min_count # Driver code arr = [ 7, 8, 4, 5, 4, 1, 1, 7, 7, 2, 5] n = len(arr) print(findDiff(arr,n)) # This code is contributed by Shrikant13
linear
linear
# Python 3 program to find minimum range # that contains exactly k distinct numbers. # Prints the minimum range that contains # exactly k distinct numbers. def minRange(arr, n, k): l = 0 r = n # Consider every element as # starting point. for i in range(n): # Find the smallest window starting # with arr[i] and containing exactly # k distinct elements. s = [] for j in range(i, n) : s.append(arr[j]) if (len(s) == k): if ((j - i) < (r - l)) : r = j l = i break # There are less than k distinct # elements now, so no need to continue. if (j == n): break # If there was no window with k distinct # elements (k is greater than total # distinct elements) if (l == 0 and r == n): print("Invalid k") else: print(l, r) # Driver code if __name__ == "__main__": arr = [ 1, 2, 3, 4, 5 ] n = len(arr) k = 3 minRange(arr, n, k) # This code is contributed # by ChitraNayal
linear
quadratic
# Python3 program to find the minimum range # that contains exactly k distinct numbers. from collections import defaultdict # Prints the minimum range that contains # exactly k distinct numbers. def minRange(arr, n, k): # Initially left and right side is -1 # and -1, number of distinct elements # are zero and range is n. l, r = 0, n i = 0 j = -1 # Initialize right side hm = defaultdict(lambda:0) while i < n: while j < n: # increment right side. j += 1 # if number of distinct elements less than k. if len(hm) < k and j < n: hm[arr[j]] += 1 # if distinct elements are equal to k # and length is less than previous length. if len(hm) == k and ((r - l) >= (j - i)): l, r = i, j break # if number of distinct elements less # than k, then break. if len(hm) < k: break # if distinct elements equals to k then # try to increment left side. while len(hm) == k: if hm[arr[i]] == 1: del(hm[arr[i]]) else: hm[arr[i]] -= 1 # increment left side. i += 1 # it is same as explained in above loop. if len(hm) == k and (r - l) >= (j - i): l, r = i, j if hm[arr[i]] == 1: del(hm[arr[i]]) else: hm[arr[i]] -= 1 i += 1 if l == 0 and r == n: print("Invalid k") else: print(l, r) # Driver code for above function. if __name__ == "__main__": arr = [1, 1, 2, 2, 3, 3, 4, 5] n = len(arr) k = 3 minRange(arr, n, k) # This code is contributed by Rituraj Jain
constant
linear
# Python 3 program to find longest # subarray with k or less distinct elements. # function to print the longest sub-array import collections def longest(a, n, k): freq = collections.defaultdict(int) start = 0 end = 0 now = 0 l = 0 for i in range(n): # mark the element visited freq[a[i]] += 1 # if its visited first time, then increase # the counter of distinct elements by 1 if (freq[a[i]] == 1): now += 1 # When the counter of distinct elements # increases from k, then reduce it to k while (now > k) : # from the left, reduce the number # of time of visit freq[a[l]] -= 1 # if the reduced visited time element # is not present in further segment # then decrease the count of distinct # elements if (freq[a[l]] == 0): now -= 1 # increase the subsegment mark l += 1 # check length of longest sub-segment # when greater than previous best # then change it if (i - l + 1 >= end - start + 1): end = i start = l # print the longest sub-segment for i in range(start, end + 1): print(a[i], end = " ") # Driver Code if __name__ == "__main__": a = [ 6, 5, 1, 2, 3, 2, 1, 4, 5 ] n = len(a) k = 3 longest(a, n, k) # This code is contributed # by ChitraNayal
linear
linear
# Python3 program to find number of pairs # in an array such that their XOR is 0 # Function to calculate the count def calculate(a) : # Sorting the list using # built in function a.sort() count = 1 answer = 0 # Traversing through the elements for i in range(1, len(a)) : if a[i] == a[i - 1] : # Counting frequency of each elements count += 1 else : # Adding the contribution of # the frequency to the answer answer = answer + count * (count - 1) // 2 count = 1 answer = answer + count * (count - 1) // 2 return answer # Driver Code if __name__ == '__main__': a = [1, 2, 1, 2, 4] # Print the count print(calculate(a))
constant
nlogn
# Python3 program to find number of pairs # in an array such that their XOR is 0 # Function to calculate the answer def calculate(a) : # Finding the maximum of the array maximum = max(a) # Creating frequency array # With initial value 0 frequency = [0 for x in range(maximum + 1)] # Traversing through the array for i in a : # Counting frequency frequency[i] += 1 answer = 0 # Traversing through the frequency array for i in frequency : # Calculating answer answer = answer + i * (i - 1) // 2 return answer # Driver Code a = [1, 2, 1, 2, 4] print(calculate(a))
linear
linear
# Python3 program to print the maximum elements # giving second array higher priority # Function to maximize array elements def maximizeArray(arr1, arr2, n): # Auxiliary array arr3 to store # elements of arr1 & arr2 arr3 = [0] * (2 * n) k = 0 for i in range(n): arr3[k] = arr1[i] k += 1 for i in range(n): arr3[k] = arr2[i] k += 1 # Hash table to store n largest # unique elements hash = {} # Sorting arr3 in decreasing order arr3 = sorted(arr3) arr3 = arr3[::-1] # Finding n largest unique elements # from arr3 and storing in hash i = 0 while (len(hash) != n): # If arr3 element not present in hash, # then store this element in hash if (arr3[i] not in hash): hash[arr3[i]] = 1 i += 1 # Store that elements of arr2 in arr3 # that are present in hash k = 0 for i in range(n): # If arr2 element is present in # hash, store it in arr3 if (arr2[i] in hash): arr3[k] = arr2[i] k += 1 del hash[arr2[i]] # Store that elements of arr1 in arr3 # that are present in hash for i in range(n): # If arr1 element is present # in hash, store it in arr3 if (arr1[i] in hash): arr3[k] = arr1[i] k += 1 del hash[arr1[i]] # Copying 1st n elements of # arr3 to arr1 for i in range(n): arr1[i] = arr3[i] # Function to print array elements def printArray(arr, n): for i in arr: print(i, end = " ") print() # Driver Code if __name__ == '__main__': array1 = [ 7, 4, 8, 0, 1 ] array2 = [ 9, 7, 2, 3, 6 ] size = len(array1) maximizeArray(array1, array2, size) printArray(array1, size) # This code is contributed by mohit kumar 29
linear
nlogn
# Python3 implementation to count # subarrays with equal number # of 1's and 0's # function to count subarrays with # equal number of 1's and 0's def countSubarrWithEqualZeroAndOne(arr, n): # 'um' implemented as hash table # to store frequency of values # obtained through cumulative sum um = dict() curr_sum = 0 # Traverse original array and compute # cumulative sum and increase count # by 1 for this sum in 'um'. # Adds '-1' when arr[i] == 0 for i in range(n): curr_sum += (-1 if (arr[i] == 0) else arr[i]) if um.get(curr_sum): um[curr_sum] += 1 else: um[curr_sum] = 1 count = 0 # traverse the hash table 'um' for itr in um: # If there are more than one # prefix subarrays with a # particular sum if um[itr] > 1: count += ((um[itr] * int(um[itr] - 1)) / 2) # add the subarrays starting from # 1st element and have equal # number of 1's and 0's if um.get(0): count += um[0] # required count of subarrays return int(count) # Driver code to test above arr = [1, 0, 0, 1, 0, 1, 1] n = len(arr) print("Count =", countSubarrWithEqualZeroAndOne(arr, n)) # This code is contributed by "Sharad_Bhardwaj".
linear
linear
# Python3 implementation to count subarrays # with equal number of 1's and 0's def countSubarrWithEqualZeroAndOne(arr, n): mp = dict() Sum = 0 count = 0 for i in range(n): # Replacing 0's in array with -1 if (arr[i] == 0): arr[i] = -1 Sum += arr[i] # If Sum = 0, it implies number of # 0's and 1's are equal from arr[0]..arr[i] if (Sum == 0): count += 1 if (Sum in mp.keys()): count += mp[Sum] mp[Sum] = mp.get(Sum, 0) + 1 return count # Driver Code arr = [1, 0, 0, 1, 0, 1, 1] n = len(arr) print("count =", countSubarrWithEqualZeroAndOne(arr, n)) # This code is contributed by mohit kumar
linear
linear
# Python 3 implementation to find the length of # longest subarray having count of 1's one # more than count of 0's # function to find the length of longest # subarray having count of 1's one more # than count of 0's def lenOfLongSubarr(arr, n): # unordered_map 'um' implemented as # hash table um = {} sum = 0 maxLen = 0 # traverse the given array for i in range(n): # consider '0' as '-1' if arr[i] == 0: sum += -1 else: sum += 1 # when subarray starts form index '0' if (sum == 1): maxLen = i + 1 # make an entry for 'sum' if it is # not present in 'um' elif (sum not in um): um[sum] = i # check if 'sum-1' is present in 'um' # or not if ((sum - 1) in um): # update maxLength if (maxLen < (i - um[sum - 1])): maxLen = i - um[sum - 1] # required maximum length return maxLen # Driver code if __name__ == '__main__': arr = [0, 1, 1, 0, 0, 1] n = len(arr) print("Length =", lenOfLongSubarr(arr, n)) # This code is contributed by # Surendra_Gangwar
linear
linear
# Python3 program to find substring with equal # number of 0's, 1's and 2's # Method to count number of substring which # has equal 0, 1 and 2 def getSubstringWithEqual012(string): N = len(string) # map to store, how many times a difference # pair has occurred previously mp = dict() mp[(0, 0)] = 1 # zc (Count of zeroes), oc(Count of 1s) # and tc(count of twos) # In starting all counts are zero zc, oc, tc = 0, 0, 0 # looping into string res = 0 # Initialize result for i in range(N): # increasing the count of current character if string[i] == '0': zc += 1 elif string[i] == '1': oc += 1 else: tc += 1 # Assuming that string doesn't contain # other characters # making pair of differences (z[i] - o[i], # z[i] - t[i]) tmp = (zc - oc, zc - tc) # Count of previous occurrences of above pair # indicates that the subarrays forming from # every previous occurrence to this occurrence # is a subarray with equal number of 0's, 1's # and 2's if tmp not in mp: res += 0 else: res += mp[tmp] # increasing the count of current difference # pair by 1 if tmp in mp: mp[tmp] += 1 else: mp[tmp] = 1 return res # Driver's Code if __name__ == "__main__": string = "0102010" print(getSubstringWithEqual012(string)) # This code is contributed by # sanjeev2552
linear
nlogn
# Python program to print all # triplets in given array # that form Arithmetic # Progression # Function to print # all triplets in # given sorted array # that forms AP def printAllAPTriplets(arr, n) : s = []; for i in range(0, n - 1) : for j in range(i + 1, n) : # Use hash to find if # there is a previous # element with difference # equal to arr[j] - arr[i] diff = arr[j] - arr[i]; if ((arr[i] - diff) in arr) : print ("{} {} {}" . format((arr[i] - diff), arr[i], arr[j]), end = "\n"); s.append(arr[i]); # Driver code arr = [2, 6, 9, 12, 17, 22, 31, 32, 35, 42]; n = len(arr); printAllAPTriplets(arr, n); # This code is contributed by # Manish Shaw(manishshaw1)
linear
quadratic
# python 3 program to print all triplets in given # array that form Arithmetic Progression # Function to print all triplets in # given sorted array that forms AP def printAllAPTriplets(arr, n): for i in range(1, n - 1): # Search other two elements of # AP with arr[i] as middle. j = i - 1 k = i + 1 while(j >= 0 and k < n ): # if a triplet is found if (arr[j] + arr[k] == 2 * arr[i]): print(arr[j], "", arr[i], "", arr[k]) # Since elements are distinct, # arr[k] and arr[j] cannot form # any more triplets with arr[i] k += 1 j -= 1 # If middle element is more move to # higher side, else move lower side. elif (arr[j] + arr[k] < 2 * arr[i]): k += 1 else: j -= 1 # Driver code arr = [ 2, 6, 9, 12, 17, 22, 31, 32, 35, 42 ] n = len(arr) printAllAPTriplets(arr, n) # This article is contributed # by Smitha Dinesh Semwal
constant
quadratic
# Python program to find unique triplets # that sum up to a given value. # Function to find unique triplets that # sum up to a given value. def findTriplets(nums, n, Sum): i = 0 j = 0 k = 0 # list to store all unique triplets. triplet = [] # list to store already found triplets # to avoid duplication. uniqTriplets = [] # Variable used to hold triplet # converted to string form. temp = "" # Variable used to store current # triplet which is stored in vector # if it is unique. newTriplet = [0, 0, 0] # Sort the input array. nums.sort() # Iterate over the array from the # start and consider it as the # first element. for i in range(n - 2): # index of the first element in # the remaining elements. j = i + 1 # index of the last element. k = n - 1 while(j < k): # If sum of triplet is equal to # given value, then check if # this triplet is unique or not. # To check uniqueness, convert # triplet to string form and # then check if this string is # present in set or not. If # triplet is unique, then store # it in list. if(nums[i] + nums[j] + nums[k] == Sum): temp = str(nums[i]) + ":" + str(nums[j]) + ":" + str(nums[k]) if temp not in uniqTriplets: uniqTriplets.append(temp) newTriplet[0] = nums[i] newTriplet[1] = nums[j] newTriplet[2] = nums[k] triplet.append(newTriplet) newTriplet = [0, 0, 0] # Increment the first index # and decrement the last # index of remaining elements. j += 1 k -= 1 # If sum is greater than given # value then to reduce sum # decrement the last index. elif(nums[i] + nums[j] + nums[k] > Sum): k -= 1 # If sum is less than given value # then to increase sum increment # the first index of remaining # elements. else: j += 1 # If no unique triplet is found, then # return 0. if(len(triplet) == 0): return 0 # Print all unique triplets stored in # list. for i in range(len(triplet)): print(triplet[i], end = ", ") return 1 # Driver Code nums = [12, 3, 6, 1, 6, 9] n = len(nums) Sum = 24 # Function call if(not findTriplets(nums, n, Sum)): print("No triplets can be formed.") # This code is contributed by rag2127
linear
quadratic
# A simple Python 3 program # to find three elements whose # sum is equal to zero # Prints all triplets in # arr[] with 0 sum def findTriplets(arr, n): found = False for i in range(0, n-2): for j in range(i+1, n-1): for k in range(j+1, n): if (arr[i] + arr[j] + arr[k] == 0): print(arr[i], arr[j], arr[k]) found = True # If no triplet with 0 sum # found in array if (found == False): print(" not exist ") # Driver code arr = [0, -1, 2, -3, 1] n = len(arr) findTriplets(arr, n) # This code is contributed by Smitha Dinesh Semwal
constant
cubic
# Python3 program to find triplets # in a given array whose sum is zero # function to print triplets with 0 sum def findTriplets(arr, n): found = False for i in range(n - 1): # Find all pairs with sum # equals to "-arr[i]" s = set() for j in range(i + 1, n): x = -(arr[i] + arr[j]) if x in s: print(x, arr[i], arr[j]) found = True else: s.add(arr[j]) if found == False: print("No Triplet Found") # Driver Code arr = [0, -1, 2, -3, 1] n = len(arr) findTriplets(arr, n) # This code is contributed by Shrikant13
linear
quadratic
# python program to find triplets in a given # array whose sum is zero # function to print triplets with 0 sum def findTriplets(arr, n): found = False # sort array elements arr.sort() for i in range(0, n-1): # initialize left and right l = i + 1 r = n - 1 x = arr[i] while (l < r): if (x + arr[l] + arr[r] == 0): # print elements if it's sum is zero print(x, arr[l], arr[r]) l += 1 r -= 1 found = True # If sum of three elements is less # than zero then increment in left elif (x + arr[l] + arr[r] < 0): l += 1 # if sum is greater than zero then # decrement in right side else: r -= 1 if (found == False): print(" No Triplet Found") # Driven source arr = [0, -1, 2, -3, 1] n = len(arr) findTriplets(arr, n) # This code is contributed by Smitha Dinesh Semwal
constant
quadratic
# Python3 program to count # triplets with given product m # Method to count such triplets def countTriplets(arr, n, m): count = 0 # Consider all triplets and count if # their product is equal to m for i in range (n - 2): for j in range (i + 1, n - 1): for k in range (j + 1, n): if (arr[i] * arr[j] * arr[k] == m): count += 1 return count # Driver code if __name__ == "__main__": arr = [1, 4, 6, 2, 3, 8] m = 24 print(countTriplets(arr, len(arr), m)) # This code is contributed by Chitranayal
constant
cubic
# Python3 program for the above approach # Function to find the triplet def countTriplets(li,product): flag = 0 count = 0 # Consider all pairs and check # for a third number so their # product is equal to product for i in range(len(li)): # Check if current pair # divides product or not # If yes, then search for # (product / li[i]*li[j]) if li[i]!= 0 and product % li[i] == 0: for j in range(i+1, len(li)): # Check if the third number is present # in the map and it is not equal to any # other two elements and also check if # this triplet is not counted already # using their indexes if li[j]!= 0 and product % (li[j]*li[i]) == 0: if product // (li[j]*li[i]) in li: n = li.index(product//(li[j]*li[i])) if n > i and n > j: flag = 1 count+=1 print(count) # Driver code li = [ 1, 4, 6, 2, 3, 8 ] product = 24 # Function call countTriplets(li,product)
linear
quadratic
# Python3 program to # count of pairs with equal # elements in an array. # Return the number of # pairs with equal values. def countPairs(arr, n): ans = 0 # for each index i and j for i in range(0 , n): for j in range(i + 1, n): # finding the index # with same value but # different index. if (arr[i] == arr[j]): ans += 1 return ans # Driven Code arr = [1, 1, 2 ] n = len(arr) print(countPairs(arr, n)) # This code is contributed # by Smitha
constant
quadratic
# Python3 program to count of index pairs # with equal elements in an array. import math as mt # Return the number of pairs with # equal values. def countPairs(arr, n): mp = dict() # Finding frequency of each number. for i in range(n): if arr[i] in mp.keys(): mp[arr[i]] += 1 else: mp[arr[i]] = 1 # Calculating pairs of each value. ans = 0 for it in mp: count = mp[it] ans += (count * (count - 1)) // 2 return ans # Driver Code arr = [1, 1, 2] n = len(arr) print(countPairs(arr, n)) # This code is contributed by mohit kumar 29
linear
linear
# Python program to find total # count of an element in a range # Returns count of element # in arr[left-1..right-1] def findFrequency(arr, n, left, right, element): count = 0 for i in range(left - 1, right): if (arr[i] == element): count += 1 return count # Driver Code arr = [2, 8, 6, 9, 8, 6, 8, 2, 11] n = len(arr) # Print frequency of 2 from position 1 to 6 print("Frequency of 2 from 1 to 6 = ", findFrequency(arr, n, 1, 6, 2)) # Print frequency of 8 from position 4 to 9 print("Frequency of 8 from 4 to 9 = ", findFrequency(arr, n, 4, 9, 8)) # This code is contributed by Anant Agarwal.
constant
linear
# python program for above implementation # Function to count numbers to be added def countNum(arr, n): count = 0 # Sort the array arr.sort() # Check if elements are consecutive # or not. If not, update count for i in range(0, n-1): if (arr[i] != arr[i+1] and arr[i] != arr[i + 1] - 1): count += arr[i + 1] - arr[i] - 1; return count # Drivers code arr = [ 3, 5, 8, 6 ] n = len(arr) print(countNum(arr, n)) # This code is contributed by Sam007
constant
nlogn
# Function to count numbers to be added def countNum(arr, n): s = dict() count, maxm, minm = 0, -10**9, 10**9 # Make a hash of elements and store # minimum and maximum element for i in range(n): s[arr[i]] = 1 if (arr[i] < minm): minm = arr[i] if (arr[i] > maxm): maxm = arr[i] # Traverse all elements from minimum # to maximum and count if it is not # in the hash for i in range(minm, maxm + 1): if i not in s.keys(): count += 1 return count # Driver code arr = [3, 5, 8, 6 ] n = len(arr) print(countNum(arr, n)) # This code is contributed by mohit kumar
constant
linear
# Python 3 program to calculate sum of # lengths of subarrays of distinct elements. # Returns sum of lengths of all subarrays # with distinct elements. def sumoflength(arr, n): # For maintaining distinct elements. s = [] # Initialize ending point and result j = 0 ans = 0 # Fix starting point for i in range(n): # Find ending point for current # subarray with distinct elements. while (j < n and (arr[j] not in s)): s.append(arr[j]) j += 1 # Calculating and adding all possible # length subarrays in arr[i..j] ans += ((j - i) * (j - i + 1)) // 2 # Remove arr[i] as we pick new # starting point from next s.remove(arr[i]) return ans # Driven Code if __name__=="__main__": arr = [1, 2, 3, 4] n = len(arr) print(sumoflength(arr, n)) # This code is contributed by ita_c
linear
linear
# Python3 program Count total number of # sub-arrays having total distinct elements # same as that original array. # Function to calculate distinct sub-array def countDistictSubarray(arr, n): # Count distinct elements in whole array vis = dict() for i in range(n): vis[arr[i]] = 1 k = len(vis) # Reset the container by removing # all elements vid = dict() # Use sliding window concept to find # count of subarrays having k distinct # elements. ans = 0 right = 0 window = 0 for left in range(n): while (right < n and window < k): if arr[right] in vid.keys(): vid[ arr[right] ] += 1 else: vid[ arr[right] ] = 1 if (vid[ arr[right] ] == 1): window += 1 right += 1 # If window size equals to array distinct # element size, then update answer if (window == k): ans += (n - right + 1) # Decrease the frequency of previous # element for next sliding window vid[ arr[left] ] -= 1 # If frequency is zero then decrease # the window size if (vid[ arr[left] ] == 0): window -= 1 return ans # Driver code arr = [2, 1, 3, 2, 3] n = len(arr) print(countDistictSubarray(arr, n)) # This code is contributed by # mohit kumar 29
linear
linear
# Python3 program to find largest consecutive # numbers present in arr. def findLongestConseqSubseq(arr, n): '''We insert all the array elements into unordered set.''' S = set(); for i in range(n): S.add(arr[i]); # check each possible sequence from the start # then update optimal length ans = 0; for i in range(n): # if current element is the starting # element of a sequence if S.__contains__(arr[i]): # Then check for next elements in the # sequence j = arr[i]; # increment the value of array element # and repeat search in the set while(S.__contains__(j)): j += 1; # Update optimal length if this length # is more. To get the length as it is # incremented one by one ans = max(ans, j - arr[i]); return ans; # Driver code if __name__ == '__main__': arr = [ 1, 94, 93, 1000, 5, 92, 78 ]; n = len(arr); print(findLongestConseqSubseq(arr, n)); # This code is contributed by 29AjayKumar
linear
quadratic
# Python3 program to implement the # above approach # Make a set of maximum elements # from two arrays A[] and B[] from collections import defaultdict def maximizeTheFirstArray(A, B, n): # Create copies of A[] and B[] # and sort the copies in # descending order. temp1 = A.copy() temp2 = B.copy() temp1.sort(reverse = True) temp2.sort(reverse = True) # Put maximum n distinct # elements of both sorted # arrays in a map. m = defaultdict(int) i = 0 j = 0; while (len(m) < n): if (temp1[i] >= temp2[j]): m[temp1[i]] += 1 i += 1 else: m[temp2[j]] += 1 j += 1 # Copy elements of A[] to that # are present in hash m. res = [] for i in range (n): if (A[i] in m): res.append(A[i]) # Copy elements of B[] to that # are present in hash m. This time # we also check if the element did # not appear twice. for i in range (n): if (B[i] in m and m[B[i]] == 1): res.append(B[i]) # Print result for i in range (n): print (res[i], end = " ") # Driver code if __name__ == "__main__": A = [9, 7, 2, 3, 6] B = [7, 4, 8, 0, 1] n = len(A) maximizeTheFirstArray(A, B, n); # This code is contributed by Chitranayal
linear
nlogn
# Python3 implementation to # find the maximum number # of chocolates to be # distributed equally # among k students # function to find the # maximum number of chocolates # to be distributed equally # among k students def maxNumOfChocolates(arr, n, k): um, curr_rem, maxSum = {}, 0, 0 # 'sm[]' to store cumulative sm, # where sm[i] = sm(arr[0]+..arr[i]) sm = [0]*n sm[0] = arr[0] # building up 'sm[]' for i in range(1, n): sm[i] = sm[i - 1] + arr[i] # traversing 'sm[]' for i in range(n): # finding current remainder curr_rem = sm[i] % k if (not curr_rem and maxSum < sm[i]) : maxSum = sm[i] elif (not curr_rem in um) : um[curr_rem] = i elif (maxSum < (sm[i] - sm[um[curr_rem]])): maxSum = sm[i] - sm[um[curr_rem]] return maxSum//k # Driver program to test above arr = [ 2, 7, 6, 1, 4, 5 ] n, k = len(arr), 3 print("Maximum number of chocolates: " + str(maxNumOfChocolates(arr, n, k))) # This code is contributed by Ansu Kumari
linear
linear
# Python 3 program to print n-th # number in Recaman's sequence # Prints first n terms of Recaman # sequence def recaman(n): # Create an array to store terms arr = [0] * n # First term of the sequence # is always 0 arr[0] = 0 print(arr[0], end=", ") # Fill remaining terms using # recursive formula. for i in range(1, n): curr = arr[i-1] - i for j in range(0, i): # If arr[i-1] - i is # negative or already # exists. if ((arr[j] == curr) or curr < 0): curr = arr[i-1] + i break arr[i] = curr print(arr[i], end=", ") # Driver code n = 17 recaman(n) # This code is contributed by Smitha.
linear
quadratic
# Python3 program to print n-th number in # Recaman's sequence # Prints first n terms of Recaman sequence def recaman(n): if(n <= 0): return # Print first term and store it in a hash print(0, ",", end='') s = set([]) s.add(0) # Print remaining terms using recursive # formula. prev = 0 for i in range(1, n): curr = prev - i # If arr[i-1] - i is negative or # already exists. if(curr < 0 or curr in s): curr = prev + i s.add(curr) print(curr, ",", end='') prev = curr # Driver code if __name__=='__main__': n = 17 recaman(n) # This code is contributed by # Sanjit_Prasad
linear
linear
# python3 program to find largest Fibonacci subset # Prints largest subset of an array whose # all elements are fibonacci numbers def findFibSubset(arr, n): #Now iterate through all elements of the array.. for i in range(n): #we are using the property of fibonacci series to check arr[i] is a # fib number or not by checking whether any one out of 5(n^2)+4 and 5(n^2)-4 # is a perfect square or not. fact1=5*(arr[i]**2)+4 fact2=5*(arr[i]**2)-4 if int(fact1**(.5))**2==fact1 or int(fact2**(.5))**2==fact2: print(arr[i],end=" ") return None # Driver code if __name__ == "__main__": arr = [4, 2, 8, 5, 20, 1, 40, 13, 23] n = len(arr) findFibSubset(arr, n) # This code is contributed by Rajat Kumar (GLA University)
constant
linear
# python3 program to find largest Fibonacci subset # Prints largest subset of an array whose # all elements are fibonacci numbers def findFibSubset(arr, n): # Find maximum element in arr[] m= max(arr) # Generate all Fibonacci numbers till # max and store them in hash. a = 0 b = 1 hash = [] hash.append(a) hash.append(b) while (b < m): c = a + b a = b b = c hash.append(b) # Npw iterate through all numbers and # quickly check for Fibonacci using # hash. for i in range (n): if arr[i] in hash : print( arr[i],end=" ") # Driver code if __name__ == "__main__": arr = [4, 2, 8, 5, 20, 1, 40, 13, 23] n = len(arr) findFibSubset(arr, n)
linear
linear
# Python3 program to find averages of # all levels in a binary tree. # Helper function that allocates a # new node with the given data and # None left and right pointers. class newNode: def __init__(self, data): self.data = data self.left = self.right = None def inorder(node, m): if (not node): return "" Str = "(" Str += inorder(node.left, m) Str += str(node.data) Str += inorder(node.right, m) Str += ")" # Subtree already present (Note that # we use unordered_map instead of # unordered_set because we want to print # multiple duplicates only once, consider # example of 4 in above subtree, it # should be printed only once. if (Str in m and m[Str] == 1): print(node.data, end = " ") if Str in m: m[Str] += 1 else: m[Str] = 1 return Str # Wrapper over inorder() def printAllDups(root): m = {} inorder(root, m) # Driver code if __name__ == '__main__': root = None root = newNode(1) root.left = newNode(2) root.right = newNode(3) root.left.left = newNode(4) root.right.left = newNode(2) root.right.left.left = newNode(4) root.right.right = newNode(4) printAllDups(root) # This code is contributed by PranchalK
quadratic
quadratic
# A brute force approach based Python3 program to # find if there is a rectangle with 1 as corners. # Returns true if there is a rectangle # with 1 as corners. def isRectangle(m): # finding row and column size rows = len(m) if (rows == 0): return False columns = len(m[0]) # scanning the matrix for y1 in range(rows): for x1 in range(columns): # if any index found 1 then # try for all rectangles if (m[y1][x1] == 1): for y2 in range(y1 + 1, rows): for x2 in range(x1 + 1, columns): if (m[y1][x2] == 1 and m[y2][x1] == 1 and m[y2][x2] == 1): return True return False # Driver code mat = [[1, 0, 0, 1, 0], [0, 0, 1, 0, 1], [0, 0, 0, 1, 0], [1, 0, 1, 0, 1]] if (isRectangle(mat)): print("Yes") else: print("No") # This code is contributed # by mohit kumar 29
constant
quadratic
# An efficient approach based Python program # to find if there is a rectangle with 1 as # corners. # Returns true if there is a rectangle # with 1 as corners. def isRectangle(matrix): # finding row and column size rows = len(matrix) if (rows == 0): return False columns = len(matrix[0]) # map for storing the index of # combination of 2 1's table = {} # scanning from top to bottom # line by line for i in range(rows): for j in range(columns - 1): for k in range(j + 1, columns): # if found two 1's in a column if (matrix[i][j] == 1 and matrix[i][k] == 1): # check if there exists 1's in same # row previously then return true if (j in table and k in table[j]): return True if (k in table and j in table[k]): return True # store the indexes in hashset if j not in table: table[j] = set() if k not in table: table[k] = set() table[j].add(k) table[k].add(j) return False # Driver Code if __name__ == '__main__': mat = [[ 1, 0, 0, 1, 0 ], [ 0, 0, 1, 0, 1 ], [ 0, 0, 0, 1, 0 ], [ 1, 0, 1, 0, 1 ]] if (isRectangle(mat)): print("Yes") else: print("No") # This code is contributed # by SHUBHAMSINGH10
quadratic
quadratic
# Python3 implementation comes from: # https:#github.com/MichaelWehar/FourCornersProblem # Written by Niteesh Kumar and Michael Wehar # References: # [1] F. Mráz, D. Prusa, and M. Wehar. # Two-dimensional Pattern Matching against # Basic Picture Languages. CIAA 2019. # [2] D. Prusa and M. Wehar. Complexity of # Searching for 2 by 2 Submatrices in Boolean # Matrices. DLT 2020. def searchForRectangle( rows, cols, mat) : # Make sure that matrix is non-trivial if (rows < 2 or cols < 2) : return False; # Create map adjsList = dict(); if (rows >= cols): # Row-wise num_of_keys = rows; # Convert each row into vector of col indexes for i in range(rows): for j in range(cols): if (mat[i][j]): if i not in adjsList: adjsList[i] = [] adjsList[i].append(j); else : # Col-wise num_of_keys = cols; # Convert each col into vector of row indexes for i in range(rows): for j in range(cols): if (mat[i][j] == 1) : if j not in adjsList: adjsList[j] = [] adjsList[j].append(i); # Search for a rectangle whose four corners are 1's pairs = dict(); for i in range(num_of_keys): values = adjsList[i]; size = len(values) for j in range(size - 1): for k in range(j + 1, size): temp = (values[j], values[k]); if temp in pairs: return True; else: pairs[temp] = i; return False; # Driver code mat = [[ 1, 0, 0, 1, 0 ], [ 0, 1, 1, 1, 1 ], [ 0, 0, 0, 1, 0 ], [ 1, 1, 1, 1, 0 ]]; if (searchForRectangle(4, 5, mat)): print("Yes"); else: print("No") # This code is contributed by phasing17.
quadratic
quadratic
# Python3 program for finding # maximum area possible of # a rectangle # function for finding # max area def findArea(arr, n): # sort array in # non-increasing order arr.sort(reverse = True) # Initialize two # sides of rectangle dimension = [0, 0] # traverse through array i = 0 j = 0 while(i < n - 1 and j < 2): # if any element occurs twice # store that as dimension if (arr[i] == arr[i + 1]): dimension[j] = arr[i] j += 1 i += 1 i += 1 # return the product # of dimensions return (dimension[0] * dimension[1]) # Driver code arr = [4, 2, 1, 4, 6, 6, 2, 5] n = len(arr) print(findArea(arr, n)) # This code is contributed # by Smitha
constant
nlogn
# Python 3 program for finding maximum # area possible of a rectangle # function for finding max area def findArea(arr, n): s = [] # traverse through array first = 0 second = 0 for i in range(n) : # If this is first occurrence of # arr[i], simply insert and continue if arr[i] not in s: s.append(arr[i]) continue # If this is second (or more) occurrence, # update first and second maximum values. if (arr[i] > first) : second = first first = arr[i] else if (arr[i] > second): second = arr[i] # return the product of dimensions return (first * second) # Driver Code if __name__ == "__main__": arr = [ 4, 2, 1, 4, 6, 6, 2, 5 ] n = len(arr) print(findArea(arr, n)) # This code is contributed by ita_c
linear
linear
# Python3 implementation to find length of # longest strict bitonic subsequence # function to find length of longest # strict bitonic subsequence def longLenStrictBitonicSub(arr, n): # hash table to map the array element # with the length of the longest subsequence # of which it is a part of and is the # last/first element of that subsequence inc, dcr = dict(), dict() # arrays to store the length of increasing # and decreasing subsequences which end at # them or start from them len_inc, len_dcr = [0] * n, [0] * n # to store the length of longest strict # bitonic subsequence longLen = 0 # traverse the array elements # from left to right for i in range(n): # initialize current length # for element arr[i] as 0 len = 0 # if 'arr[i]-1' is in 'inc' if inc.get(arr[i] - 1) in inc.values(): len = inc.get(arr[i] - 1) # update arr[i] subsequence length in 'inc' # and in len_inc[] inc[arr[i]] = len_inc[i] = len + 1 # traverse the array elements # from right to left for i in range(n - 1, -1, -1): # initialize current length # for element arr[i] as 0 len = 0 # if 'arr[i]-1' is in 'dcr' if dcr.get(arr[i] - 1) in dcr.values(): len = dcr.get(arr[i] - 1) # update arr[i] subsequence length # in 'dcr' and in len_dcr[] dcr[arr[i]] = len_dcr[i] = len + 1 # calculating the length of # all the strict bitonic subsequence for i in range(n): if longLen < (len_inc[i] + len_dcr[i] - 1): longLen = len_inc[i] + len_dcr[i] - 1 # required longest length strict # bitonic subsequence return longLen # Driver Code if __name__ == "__main__": arr = [1, 5, 2, 3, 4, 5, 3, 2] n = len(arr) print("Longest length strict bitonic subsequence =", longLenStrictBitonicSub(arr, n)) # This code is contributed by sanjeev2552
linear
linear
# Python3 program to find last seen # element in an array. import sys; # Returns last seen element in arr[] def lastSeenElement(a, n): # Store last occurrence index of # every element hash = {} for i in range(n): hash[a[i]] = i # Find an element in hash with minimum # index value res_ind = sys.maxsize res = 0 for x, y in hash.items(): if y < res_ind: res_ind = y res = x return res # Driver code if __name__=="__main__": a = [ 2, 1, 2, 2, 4, 1 ] n = len(a) print(lastSeenElement(a,n)) # This code is contributed by rutvik_56
linear
linear
# Python program to delete a node in a linked list # at a given position # Node class class Node: # Constructor to initialize the node object def __init__(self, data): self.data = data self.next = None class LinkedList: # Constructor to initialize head def __init__(self): self.head = None # Function to insert a new node at the beginning def push(self, new_data): new_node = Node(new_data) new_node.next = self.head self.head = new_node # Given a reference to the head of a list # and a position, delete the node at a given position # This delete function code is contributed by Arabin Islam def deleteNodeAtGivenPosition(self, position): if self.head is None: return index = 0 current = self.head while current.next and index < position: previous = current current = current.next index += 1 if index < position: print("\nIndex is out of range.") elif index == 0: self.head = self.head.next else: previous.next = current.next # current = None #Optional statement # Utility function to print the LinkedList def printList(self): temp = self.head while(temp): print(" %d " % (temp.data), end=" ") temp = temp.next # Driver program to test above function llist = LinkedList() llist.push(7) llist.push(1) llist.push(3) llist.push(2) llist.push(8) print("Created Linked List: ") llist.printList() llist.deleteNodeAtGivenPosition(4) print("\nLinked List after Deletion at position 4: ") llist.printList() # This code is contributed by Nikhil Kumar Singh(nickzuck_007)
constant
linear
# Python3 program to delete all # the nodes of singly linked list # Node class class Node: # Function to initialise the node object def __init__(self, data): self.data = data # Assign data self.next = None # Initialize next as null # Constructor to initialize the node object class LinkedList: # Function to initialize head def __init__(self): self.head = None def deleteList(self): # initialize the current node current = self.head while current: next_to_current = current.next # move next node # delete the current node del current.data # set current equals prev node current = next_to_current # In python garbage collection happens # therefore, only # self.head = None # would also delete the link list # push function to add node in front of llist def push(self, new_data): # Allocate the Node & # Put in the data new_node = Node(new_data) # Make next of new Node as head new_node.next = self.head # Move the head to point to new Node self.head = new_node # Use push() to construct below # list 1-> 12-> 1-> 4-> 1 if __name__ == '__main__': llist = LinkedList() llist.push(1) llist.push(4) llist.push(1) llist.push(12) llist.push(1) print("Deleting linked list") llist.deleteList() print("Linked list deleted") # This article is provided by Shrikant13
constant
linear
# A complete working Python program to find length of a # Linked List iteratively # Node class class Node: # Function to initialise the node object def __init__(self, data): self.data = data # Assign data self.next = None # Initialize next as null # Linked List class contains a Node object class LinkedList: # Function to initialize head def __init__(self): self.head = None # This function is in LinkedList class. It inserts # a new node at the beginning of Linked List. def push(self, new_data): # 1 & 2: Allocate the Node & # Put in the data new_node = Node(new_data) # 3. Make next of new Node as head new_node.next = self.head # 4. Move the head to point to new Node self.head = new_node # This function counts number of nodes in Linked List # iteratively, given 'node' as starting node. def getCount(self): temp = self.head # Initialise temp count = 0 # Initialise count # Loop while end of linked list is not reached while (temp): count += 1 temp = temp.next return count # Driver code if __name__ == '__main__': llist = LinkedList() llist.push(1) llist.push(3) llist.push(1) llist.push(2) llist.push(1) # Function call print("Count of nodes is :", llist.getCount())
constant
linear
# A complete working Python program to find length of a # Linked List recursively # Node class class Node: # Function to initialise the node object def __init__(self, data): self.data = data # Assign data self.next = None # Initialize next as null # Linked List class contains a Node object class LinkedList: # Function to initialize head def __init__(self): self.head = None # This function is in LinkedList class. It inserts # a new node at the beginning of Linked List. def push(self, new_data): # 1 & 2: Allocate the Node & # Put in the data new_node = Node(new_data) # 3. Make next of new Node as head new_node.next = self.head # 4. Move the head to point to new Node self.head = new_node # This function counts number of nodes in Linked List # recursively, given 'node' as starting node. def getCountRec(self, node): if (not node): # Base case return 0 else: return 1 + self.getCountRec(node.next) # A wrapper over getCountRec() def getCount(self): return self.getCountRec(self.head) # Code execution starts here if __name__ == '__main__': llist = LinkedList() llist.push(1) llist.push(3) llist.push(1) llist.push(2) llist.push(1) print('Count of nodes is :', llist.getCount())
linear
linear
# A complete working Python3 program to find length of a # Linked List using Tail recursion. # Node class class Node: # Function to initialise the node object def __init__(self, data): self.data = data # Assign data self.next = None # Initialize next as null # Linked List class contains a Node object class LinkedList: # Function to initialize head def __init__(self): self.head = None # This function is in LinkedList class. It inserts # a new node at the beginning of Linked List. def push(self, new_data): # 1 & 2: Allocate the Node & # Put in the data new_node = Node(new_data) # 3. Make next of new Node as head new_node.next = self.head # 4. Move the head to point to new Node self.head = new_node # This function counts number of nodes in Linked List # recursively, given 'node' as starting node using Tail Recursion. def getCountRec(self, node, count=0): if (not node): # Base case return count else: return self.getCountRec(node.next, count+1) # A wrapper over getCountRec() def getCount(self): return self.getCountRec(self.head) # Driver code if __name__ == '__main__': llist = LinkedList() llist.push(1) llist.push(3) llist.push(1) llist.push(2) llist.push(1) # Function call print('Count of nodes is :', llist.getCount()) # This code is contributed by garinesrija.
constant
linear
# Iterative Python3 program to search an element # in linked list # Node class class Node: # Function to initialise the node object def __init__(self, data): self.data = data # Assign data self.next = None # Initialize next as null # Linked List class class LinkedList: def __init__(self): self.head = None # Initialize head as None # This function insert a new node at the # beginning of the linked list def push(self, new_data): # Create a new Node new_node = Node(new_data) # 3. Make next of new Node as head new_node.next = self.head # 4. Move the head to point to new Node self.head = new_node # This Function checks whether the value # x present in the linked list def search(self, x): # Initialize current to head current = self.head # loop till current not equal to None while current != None: if current.data == x: return True # data found current = current.next return False # Data Not found # Driver code if __name__ == '__main__': # Start with the empty list llist = LinkedList() ''' Use push() to construct below list 14->21->11->30->10 ''' llist.push(10) llist.push(30) llist.push(11) llist.push(21) llist.push(14) # Function call if llist.search(21): print("Yes") else: print("No") # This code is contributed by Ravi Shankar
constant
linear
# Recursive Python program to # search an element in linked list # Node class class Node: # Function to initialise # the node object def __init__(self, data): self.data = data # Assign data self.next = None # Initialize next as null class LinkedList: def __init__(self): self.head = None # Initialize head as None # This function insert a new node at # the beginning of the linked list def push(self, new_data): # Create a new Node new_node = Node(new_data) # Make next of new Node as head new_node.next = self.head # Move the head to # point to new Node self.head = new_node # Checks whether the value key # is present in linked list def search(self, li, key): # Base case if(not li): return False # If key is present in # current node, return true if(li.data == key): return True # Recur for remaining list return self.search(li.next, key) # Driver Code if __name__ == '__main__': li = LinkedList() li.push(1) li.push(2) li.push(3) li.push(4) key = 4 # Function call if li.search(li.head, key): print("Yes") else: print("No") # This code is contributed # by Manoj Sharma
linear
linear