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#include <bits/stdc++.h> using namespace std; int f[505], n, ans[1000000]; int main() { int tt = 0, ttt = 0; scanf("%d", &tt); while (tt--) { scanf("%d", &n); ans[0] = 0; for (int i = 1; i <= n; i++) scanf("%d", &f[i]); for (int i = 1, j; i + 2 <= n; i++) { j = i; for (int k = i + 1; k <= n; k++) { if (f[k] < f[j]) j = k; } for (int k = j - 2, kk; k >= i; k -= 2) { kk = f[k + 2]; f[k + 2] = f[k + 1]; f[k + 1] = f[k]; f[k] = kk; j -= 2; ans[++ans[0]] = k; } if (i + 1 == j) { ans[++ans[0]] = i; ans[++ans[0]] = i; int kk = f[i]; f[i] = f[i + 1]; f[i + 1] = f[i + 2]; f[i + 2] = kk; } } bool tag = false; if (f[n] < f[n - 1]) { tag = true; for (int i = n - 2, kk; i > 0; i--) { kk = f[i + 2]; f[i + 2] = f[i + 1]; f[i + 1] = f[i]; f[i] = kk; ans[++ans[0]] = i; if (f[i] <= f[i + 1]) { tag = false; break; } } } if (tag) puts("-1"); else { printf("%d\n", ans[0]); for (int i = 1; i < ans[0]; i++) { printf("%d ", ans[i]); } if (ans[0] > 0) printf("%d\n", ans[ans[0]]); else puts(""); } } return 0; }
#include <bits/stdc++.h> using namespace std; const int N = 5e5 + 2; const int M = 4e6 + 2; const int mod = 998244353; const long long inf = 1e15; const long long INF = 2e18; void data() {} int T, n, a[N], b[N]; int main() { data(); scanf("%d", &T); while (T--) { scanf("%d", &n); for (int i = 1; i <= n; ++i) { scanf("%d", &a[i]); } int r = n; vector<int> ans; while (r >= 3) { int mx = 0; for (int i = 1; i <= r; ++i) { if (a[mx] <= a[i]) mx = i; } while (mx != r) { if (mx == r - 1) { ans.push_back(mx - 1); swap(a[mx + 1], a[mx - 1]); swap(a[mx], a[mx + 1]); mx++; } else { ans.push_back(mx); swap(a[mx + 2], a[mx]); swap(a[mx + 1], a[mx + 2]); mx++; } } r--; } bool f = 0; if (a[1] <= a[2]) f = 1; else if (a[1] == a[3]) { f = 1; ans.push_back(1); ans.push_back(1); swap(a[1 + 2], a[1]); swap(a[1 + 1], a[1 + 2]); swap(a[1 + 2], a[1]); swap(a[1 + 1], a[1 + 2]); } if (f) { printf("%d\n", (int)ans.size()); for (auto it : ans) printf("%d ", it); printf("\n"); } else { int pos = 0; for (int i = 4; i <= n; ++i) { if (a[i] == a[i - 1]) { pos = i - 1; break; } } if (!pos) { printf("-1\n"); } else { for (int i = 1; i <= pos - 3; ++i) { ans.push_back(i); swap(a[i + 2], a[i]); swap(a[i + 1], a[i + 2]); } pos--; ans.push_back(pos); swap(a[pos + 2], a[pos]); swap(a[pos + 1], a[pos + 2]); pos--; ans.push_back(pos); swap(a[pos + 2], a[pos]); swap(a[pos + 1], a[pos + 2]); pos += 2; for (int i = pos - 3; i >= 1; --i) { ans.push_back(i); ans.push_back(i); swap(a[i + 2], a[i]); swap(a[i + 1], a[i + 2]); swap(a[i + 2], a[i]); swap(a[i + 1], a[i + 2]); } printf("%d\n", (int)ans.size()); for (auto it : ans) { printf("%d ", it); } printf("\n"); } } for (int i = 1; i <= n; ++i) { cerr << a[i] << " "; } } }
#include <bits/stdc++.h> using namespace std; const long long N = 510; long long a[N]; void rot1(long long& first, long long& second, long long& z) { tie(first, second, z) = make_tuple(z, first, second); } void rot2(long long ind) { rot1(a[ind], a[ind + 1], a[ind + 2]); } signed main() { ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); long long t; cin >> t; while (t--) { long long n; cin >> n; map<long long, long long> pos; long long pos1 = 0, pos2 = 0; for (long long i = 1; i <= n; i++) { cin >> a[i]; if (pos.count(a[i])) pos1 = pos[a[i]], pos2 = i; pos[a[i]] = i; a[i] *= N; a[i] += i; } bool even = true; for (long long i = 1; i <= n; i++) for (long long j = i + 1; j <= n; j++) if (a[i] > a[j]) even = !even; if (!even) if (pos1) swap(a[pos1], a[pos2]); else { cout << -1 << "\n"; continue; } vector<long long> idx; while (true) { long long i = 1; while (i <= n && min_element(a + i, a + n + 1) == a + i) i++; if (i > n - 2) break; long long j = min_element(a + i, a + n + 1) - a; while (j - i >= 2) rot2(j - 2), idx.push_back(j - 2), j -= 2; if (j - i == 1) rot2(i), idx.push_back(i), rot2(i), idx.push_back(i); } if (is_sorted(a + 1, a + n + 1)) { cout << idx.size() << "\n"; for (long long i : idx) cout << i << " "; cout << "\n"; } else cout << -1 << "\n"; } }
#include <bits/stdc++.h> using namespace std; const int N = 200010; int T, n, mk, a[N]; vector<int> res; void flip(int x) { int t = a[x + 2]; a[x + 2] = a[x + 1]; a[x + 1] = a[x]; a[x] = t; } void solve(int x, int y) { if (a[x] == a[x + 2]) { flip(x); flip(x); res.push_back(x); res.push_back(x); return; } if (y >= n - 1) { mk = 0; return; } if (a[x + 2] == a[y + 2]) { flip(y); flip(x); res.push_back(y); res.push_back(x); return; } solve(x + 1, y + 1); flip(x); res.push_back(x); } int main() { scanf("%d", &T); while (T--) { res.clear(); scanf("%d", &n); for (int i = 1; i <= n; i++) scanf("%d", &a[i]); for (int i = n; i >= 3; i--) { int pos = 0, imax = 0; for (int k = 1; k <= i; k++) { if (a[k] > imax) { imax = a[k]; pos = k; } } if (pos == i) continue; for (int k = 0; k < i - pos - 1; k++) { res.push_back(pos + k); flip(pos + k); } flip(i - 2); res.push_back(i - 2); } if (a[1] > a[2]) { mk = 1; solve(1, 2); if (0 == mk) { printf("-1\n"); continue; } } printf("%d\n", res.size()); for (int i = 0; i < res.size(); i++) { printf("%d", res[i]); printf(i == res.size() - 1 ? "\n" : " "); } if (0 == res.size()) printf("\n"); } return 0; }
#include <bits/stdc++.h> using namespace std; void culc(int& a, int& b, int& c) { swap(b, c), swap(a, b); } void solve() { int n; cin >> n; vector<int> a(n); for (int i = 0; i < n; i++) cin >> a[i]; vector<int> ans; for (int i = 0; i < n - 2; i++) { auto it = min_element(a.begin() + i, a.end()) - a.begin(); if (i % 2 != it % 2) { if (it < n - 1) { culc(a[it - 1], a[it], a[it + 1]); ans.push_back(it - 1); it++; } else { culc(a[it - 2], a[it - 1], a[it]); culc(a[it - 2], a[it - 1], a[it]); ans.push_back(it - 2); ans.push_back(it - 2); it--; } } while (it != i) { culc(a[it - 2], a[it - 1], a[it]); ans.push_back(it - 2); it -= 2; } } bool flag = true; if (a[n - 1] < a[n - 2]) { flag = false; for (int i = n - 3; i >= 0; i--) { culc(a[i], a[i + 1], a[i + 2]); ans.push_back(i); if (a[i] <= a[i + 1]) { flag = true; break; } } } if (!flag) { cout << -1 << endl; return; } else { cout << ans.size() << endl; for (auto u : ans) cout << u + 1 << " "; cout << endl; } } int main() { int t; cin >> t; while (t--) { solve(); } }
#include <bits/stdc++.h> using namespace std; template <class c> struct rge { c b, e; }; template <class c> rge<c> range(c i, c j) { return rge<c>{i, j}; } template <class c> auto dud(c* x) -> decltype(cerr << *x, 0); template <class c> char dud(...); struct debug { template <class c> debug& operator<<(const c&) { return *this; } }; void solve() { int n; cin >> n; vector<int> a(n); for (int i = 0; i < n; i++) { cin >> a[i]; } vector<int> ans; bool ok = false; int cnt = 0, prev = -1; while (cnt < n * n && !ok) { prev = cnt; for (int i = 0; i < n - 2; i++) { if (a[i + 1] <= a[i] and a[i + 1] <= a[i + 2]) { if (n * n - cnt < 2) { break; } cnt += 2; swap(a[i], a[i + 1]); swap(a[i + 1], a[i + 2]); ans.push_back(i); ans.push_back(i); } else if (a[i + 2] <= a[i] && a[i + 2] <= a[i + 1]) { if (n * n - cnt < 1) { break; } cnt += 1; swap(a[i], a[i + 2]); swap(a[i + 1], a[i + 2]); ans.push_back(i); } } ok = true; for (int i = 0; i < n - 1; i++) { if (a[i] > a[i + 1]) { ok = false; break; } } if (!ok && prev == cnt) { break; } } if (ok) { cout << cnt << "\n"; for (int x : ans) { cout << x + 1 << " "; } cout << "\n"; } else { cout << "-1\n"; } } int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL); int t = 1; cin >> t; while (t--) { solve(); } return 0; }
#include <bits/stdc++.h> int main() { std::ios::sync_with_stdio(false); std::cin.tie(NULL); int T; std::cin >> T; while (T--) { int n; std::cin >> n; std::vector<int> a(n), cnt(500, 0), mem; for (int i = 0; i < n; i++) { std::cin >> a[i]; --a[i]; ++cnt[a[i]]; } mem = a; for (int i = 1; i < 500; i++) { cnt[i] += cnt[i - 1]; } std::vector<int> b = a; for (int i = 0; i < n; i++) b[i] = --cnt[a[i]]; a = b; std::vector<int> answer; auto solve = [&]() { for (int k = 0; k < n - 2; k++) { int mn = 1e9, pos; for (int i = k; i < n; i++) if (a[i] < mn) { mn = a[i]; pos = i; } for (int i = pos; i > k;) { if (i == k + 1) { answer.push_back(k); answer.push_back(k); --i; std::swap(a[i], a[i + 1]); std::swap(a[i], a[i + 2]); std::swap(a[i], a[i + 1]); std::swap(a[i], a[i + 2]); break; } else { answer.push_back(i - 2); i -= 2; std::swap(a[i], a[i + 1]); std::swap(a[i], a[i + 2]); } } } bool flag = true; for (int i = 1; i < n; i++) if (a[i] < a[i - 1]) { flag = false; } return flag; }; if (solve()) { std::cout << answer.size() << '\n'; for (auto i : answer) { std::cout << i + 1 << ' '; } std::cout << '\n'; } else { answer.clear(); cnt.assign(500, -1); a = mem; for (int i = 0; i < n; i++) { if (~cnt[a[i]]) { std::swap(b[cnt[a[i]]], b[i]); break; } else { cnt[a[i]] = i; } } a = b; if (solve()) { std::cout << answer.size() << '\n'; for (auto i : answer) { std::cout << i + 1 << ' '; } std::cout << '\n'; } else { std::cout << -1 << '\n'; } } } return 0; }
#include <bits/stdc++.h> using namespace std; void cyc(vector<int>& v, int i) { swap(v[i], v[i + 2]); swap(v[i + 2], v[i + 1]); } int main() { ios::sync_with_stdio(false); cin.tie(0); cout.tie(0); int t; cin >> t; while (t--) { int n; cin >> n; vector<int> a(n); vector<pair<int, int>> p(n); map<int, int> kde; pair<int, int> con = make_pair(-1, -1); for (int i = 0; i < n; i++) { cin >> a[i]; if (kde.count(a[i])) { con = make_pair(kde[a[i]], i); } kde[a[i]] = i; p[i] = make_pair(a[i], i); } sort(p.begin(), p.end()); for (int i = 0; i < n; i++) { a[p[i].second] = i; } int inv = 0; for (int i = 0; i < n; i++) { for (int j = 0; j < i; j++) if (a[j] > a[i]) inv++; } if (inv % 2 == 1 && con.first > -1) swap(a[con.first], a[con.second]); vector<int> v; if (n > 2) for (int i = n - 1; i >= 1; i--) { int in = 0; for (int j = 0; j < i + 1; j++) if (a[j] >= a[in]) { in = j; } if (in == 0) { cyc(a, 0); v.push_back(0); in++; } for (int j = in - 1; j < i - 1; j++) { cyc(a, j); v.push_back(j); } } vector<int> b = a; sort(b.begin(), b.end()); if (b == a) { cout << v.size() << endl; for (int i : v) cout << i + 1 << " "; cout << endl; } else { cout << -1 << endl; } } return 0; }
#include <bits/stdc++.h> using namespace std; int T, n, m, k; int a[555]; pair<int, int> b[555]; vector<int> ans; inline void op(int pos) { int t = a[pos + 2]; a[pos + 2] = a[pos + 1]; a[pos + 1] = a[pos]; a[pos] = t; ans.push_back(pos); } int main() { ios_base::sync_with_stdio(false); cin >> T; while (T--) { cin >> n; for (int i = 1; i <= n; i++) { cin >> a[i]; b[i] = make_pair(a[i], i); } sort(b + 1, b + n + 1); int same = -1, cnt = 0; for (int i = 1; i < n; i++) { if (b[i].first == b[i + 1].first) same = b[i].first; for (int j = i + 1; j <= n; j++) { if (b[i].second > b[j].second) cnt++; } } if (cnt % 2 != 0 && same == -1) { cout << -1 << endl; continue; } if (cnt % 2 != 0) { for (int i = 1; i < n; i++) { if (b[i].first == b[i + 1].first) { swap(b[i].second, b[i + 1].second); break; } } } for (int i = 1; i <= n; i++) a[b[i].second] = i; for (int i = 1; i <= n - 2; i++) { int pos = 0; for (int j = i; j <= n; j++) { if (a[j] == i) { pos = j; break; } } while (pos > i + 1) op(pos - 2), pos -= 2; if (pos == i + 1) op(i), op(i); } cout << ans.size() << endl; for (auto x : ans) cout << x << ' '; cout << endl; ans.clear(); } return 0; }
#include <bits/stdc++.h> #pragma optimise GCC(-O2) using namespace std; mt19937_64 rang( chrono::high_resolution_clock::now().time_since_epoch().count()); long long rng(long long lim) { uniform_int_distribution<long long> uid(0, lim - 1); return uid(rang); } long long INF = LLONG_MAX; const long long M = 1000000007, M2 = 998244353, M3 = 2013265921; long long powm(long long, long long, long long); long long modI(long long, long long); long long PrimRoot(long long p, long long x); void fft(vector<long long>& a, long long n, bool invert, long long m, long long x); void PolyMult(vector<long long>& a, vector<long long>& b, vector<long long>& v, long long m, long long x); void solve() { long long n; cin >> n; long long a[n]; for (long long i = 0; i < n; i++) cin >> a[i]; vector<long long> ans; long long b[n]; for (long long i = 0; i < n; i++) b[i] = a[i]; sort(b, b + n); for (long long i = 0; i < n - 2; i++) { for (long long j = i; j < n; j++) { if (a[j] == b[i]) { while (j != i) { ans.push_back(j - 2); swap(a[j - 2], a[j - 1]); swap(a[j - 2], a[j]); j -= 2; } goto meow; } j++; } for (long long j = i + 1; j < n; j++) { if (a[j] == b[i]) { while (j != i + 1) { ans.push_back(j - 2); swap(a[j - 2], a[j - 1]); swap(a[j - 2], a[j]); j -= 2; } ans.push_back(i); ans.push_back(i); swap(a[i], a[i + 1]); swap(a[i + 2], a[i + 1]); goto meow; } j++; } meow:; } if (a[n - 1] != b[n - 1]) { map<long long, long long> ct; bool ALLMIGHT = 0; for (long long i = 0; i < n; i++) { ct[a[i]]++; if (ct[a[i]] == 2) ALLMIGHT = 1; } if (ALLMIGHT == 0) { cout << -1 << endl; return; } long long curram_mf = n - 3; while (ALLMIGHT) { ans.push_back(curram_mf); swap(a[curram_mf], a[curram_mf + 1]); swap(a[curram_mf], a[curram_mf + 2]); curram_mf--; bool DETROITSMASH = 0; for (long long i = 0; i < n; i++) if (a[i] != b[i]) DETROITSMASH = 1; ALLMIGHT = DETROITSMASH; } } cout << ans.size() << endl; for (auto x : ans) cout << x + 1 << " "; cout << endl; return; } int32_t main() { ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL); long long t; cin >> t; while (t--) { solve(); } } long long powm(long long a, long long b, long long c = M) { long long res = 1; while (b) { if (b & 1) res = (res * a) % c; a = (a * a) % c; b >>= 1; } return res; } long long modI(long long a, long long m = M) { long long m0 = m, y = 0, x = 1; if (m == 1) return 0; while (a > 1) { long long q = a / m; long long t = m; m = a % m; a = t; t = y; y = x - q * y; x = t; } if (x < 0) x += m0; return x; } long long PrimRoot(long long p, long long x) { vector<long long> v; long long t = p - 1; for (long long i = 2; i * i <= t; i++) if (t % i == 0) { v.push_back((p - 1) / i); while (t % i == 0) t /= i; } if (t > 1) v.push_back((p - 1) / t); for (long long i = x + 1; i < p; i++) { long long flag = 0; for (auto x : v) if (powm(i, x, p) == 1) { flag = 1; break; } if (flag == 0) return i; } return 0; } void fft(vector<long long>& a, long long n, bool invert, long long m, long long x) { long long lg_n = __builtin_ctzll(n); for (long long i = 0, y = 0; i < n; i++) { for (long long j = 0; j < lg_n; j++) if ((1LL << j) & i) y |= (1LL << (lg_n - j - 1)); if (y > i) swap(a[i], a[y]); } if (invert) x = modI(x, m); for (long long s = 2; s <= n; s <<= 1) { long long y = powm(x, (n / s), m); for (long long j = 0; j < (n / s); j++) { long long r = 1; for (long long i = 0; i < s / 2; i++) { long long u = a[i + j * s], v = (r * a[i + j * s + (s / 2)]) % m; a[i + j * s] = (u + v) % m; a[i + j * s + (s / 2)] = (u - v + m) % m; r = r * y % m; } } } if (invert) { long long invn = modI(n, m); for (long long i = 0; i < n; i++) a[i] = (a[i] * invn) % m; } return; } void PolyMult(vector<long long>& a, vector<long long>& b, vector<long long>& v, long long m, long long x) { long long n = 1; while (n < ((long long)a.size()) + ((long long)b.size())) n <<= 1; vector<long long> fa(a.begin(), a.end()); fa.resize(n, 0); vector<long long> fb(b.begin(), b.end()); fb.resize(n, 0); long long y = powm(x, (m - 1) / n, m); fft(fa, n, false, m, y); fft(fb, n, false, m, y); v.resize(n, 0); for (long long i = 0; i < n; i++) v[i] = ((fa[i] * fb[i]) % m); fft(v, n, true, m, y); return; }
#include <bits/stdc++.h> #pragma GCC target("avx2") #pragma GCC optimize("Ofast") #pragma GCC optimize("unroll-loops") using namespace std; template <typename T> T sqr(T a) { return a * a; } template <typename T> int sign(T a) { if (a == 0) return 0; return (a > 0 ? 1 : -1); } template <typename T> bool uax(T& a, const T b) { if (a < b) { a = b; return true; } return false; } template <typename T> bool uin(T& a, const T b) { if (a > b) { a = b; return true; } return false; } template <typename T1, typename T2> istream& operator>>(istream& in, pair<T1, T2>& p) { in >> p.first >> p.second; return in; } template <typename T1, typename T2> ostream& operator<<(ostream& out, pair<T1, T2>& p) { out << p.first << ' ' << p.second; return out; } mt19937_64 rnd(0); const int LOG = 64; const int N = (int)2e5 + 7; const int MAXN = (int)1e6 + 7; const int MOD = (int)1e9 + 7; const int INF = (int)2e9 + 7; const int CONST = 450; const long long LINF = (int64_t)1e18; const long double PI = 3.1415926535897932384626433832795; const long double EPS = 1; vector<int> act; int n, a[N], need[N]; bool check_parity() { int inv = 0; for (int i = 0; i < n; i++) { for (int j = i + 1; j < n; j++) inv += need[i] > need[j]; } return inv % 2 == 0; } void perform(int pos) { act.push_back(pos + 1); swap(need[pos], need[pos + 1]); swap(need[pos], need[pos + 2]); } void solve() { cin >> n; act.clear(); vector<pair<int, int>> v; for (int i = 0; i < n; i++) { cin >> a[i]; v.push_back(make_pair(a[i], i)); } sort(v.begin(), v.end()); pair<int, int> eq = make_pair(-1, -1); for (int i = 0; i < n; i++) { need[v[i].second] = i; if (i && v[i - 1].first == v[i].first) eq = make_pair(v[i - 1].second, v[i].second); } if (!check_parity()) { if (eq.first == -1) { cout << "-1\n"; return; } swap(need[eq.first], need[eq.second]); } for (int i = 0; i < n; i++) { int pos; for (int j = 0; j < n; j++) { if (need[j] == i) pos = j; } if (pos % 2 != i % 2) { if (pos == n - 1) { perform(n - 3); perform(n - 3); pos = n - 2; } else { perform(pos - 1); pos++; } } while (pos != i) { perform(pos - 2); pos -= 2; } } cout << (int)act.size() << "\n"; for (int x : act) cout << x << ' '; cout << "\n"; } int main() { double start = clock(); cout << fixed << setprecision(20); ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); rnd.seed(time(0)); int t = 1; cin >> t; for (int i = 0; i < t; i++) { solve(); } }
#include <bits/stdc++.h> using namespace std; vector<int> v, ans; void op(int i) { int x = v[i + 2]; v[i + 2] = v[i + 1]; v[i + 1] = v[i]; v[i] = x; if (ans.size() >= 2 && ans[ans.size() - 1] == i + 1 && ans[ans.size() - 2] == i + 1) ans.pop_back(), ans.pop_back(); else ans.push_back(i + 1); } void reach(int x, int y) { while (y > x + 1) op(y - 2), y -= 2; if (y == x + 1) op(y - 1), op(y - 1); } int main(int argc, char **argv) { ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); int t; cin >> t; while (t--) { int n, st = 0, temp = 0; ans.clear(); cin >> n; v.resize(n); vector<int> ar(501, -1); int val = -1, x, y; for (int i = 0; i < n; i++) { cin >> v[i]; if (ar[v[i]] != -1) val = v[i], x = ar[v[i]], y = i; ar[v[i]] = i; } if (val != -1) v[x] = v[y] = 2000; while (n - st > 3) { int mi = 1000, in; for (int j = st; j < n; j++) if (v[j] < mi) mi = v[j], in = j; reach(st, in); st++; } if (val == -1) { while (!(v[st] <= v[st + 1] && v[st + 1] <= v[st + 2])) { op(st), temp++; if (temp > 5) break; } if (temp > 5) { cout << -1 << endl; continue; } } else { while (v[st + 1] != 2000 || v[st + 2] != 2000) op(st); while (st >= 0 && val < v[st]) op(st), op(st), st--; } cout << ans.size() << endl; for (auto x : ans) cout << x << " "; cout << endl; } }
#include <bits/stdc++.h> #pragma GCC optimize(2) #pragma GCC optimize(3) using namespace std; inline int read() { int x = 0, neg = 1; char op = getchar(); while (!isdigit(op)) { if (op == '-') neg = -1; op = getchar(); } while (isdigit(op)) { x = 10 * x + op - '0'; op = getchar(); } return neg * x; } inline void print(int x) { if (x < 0) { putchar('-'); x = -x; } if (x >= 10) print(x / 10); putchar(x % 10 + '0'); } const int N = 505; pair<int, int> a[N]; int p[N], n; void rotate(int x) { swap(p[x], p[x + 2]); swap(p[x + 1], p[x + 2]); } bool check() { for (register int i = 1; i < n; i++) { if (p[i] > p[i + 1]) { return 0; } } return 1; } void solve() { n = read(); for (register int i = 1; i <= n; i++) { int x = read(); a[i] = make_pair(x, i); } sort(a + 1, a + n + 1); for (register int i = 1; i <= n; i++) { p[a[i].second] = i; } int cnt = 0; for (register int i = 1; i <= n; i++) { for (register int j = i + 1; j <= n; j++) { if (p[i] > p[j]) { cnt++; } } } if (cnt & 1) { for (register int i = 1; i < n; i++) { if (a[i].first == a[i + 1].first) { swap(p[a[i].second], p[a[i + 1].second]); break; } } } vector<int> ans; for (register int i = 1; i <= n - 2; i++) { int pos = min_element(p + i, p + n + 1) - p; while (pos > i + 1) { rotate(pos - 2), ans.push_back(pos - 2); pos -= 2; } if (pos > i) { rotate(i), ans.push_back(i); rotate(i), ans.push_back(i); } } for (register int i = 0; i < 3; i++) { if (check()) break; rotate(n - 2), ans.push_back(n - 2); } if (!check()) { puts("-1"); } else { printf("%d\n", (int)ans.size()); for (auto v : ans) { printf("%d ", v); } puts(""); } } int main() { int T = read(); while (T--) solve(); return 0; }
#include <bits/stdc++.h> using namespace std; vector<int> ans; void tros(int i, vector<int> &v) { int t = v[i + 2]; v[i + 2] = v[i + 1]; v[i + 1] = v[i]; v[i] = t; } void sort(vector<int> &v) { int n = v.size(); for (int i = 0; i < n - 2; i++) { int mn = 600, id = -1; for (int j = i; j < n; j++) { if (mn <= v[j]) continue; id = j; mn = v[j]; } while (id >= i + 2) { ans.push_back(id - 2); tros(id - 2, v); id -= 2; } if (id == i + 1) { ans.push_back(id - 1); ans.push_back(id - 1); tros(id - 1, v); tros(id - 1, v); } } } bool sorted(vector<int> &v) { for (int i = 1; i < v.size(); i++) if (v[i] < v[i - 1]) return 0; return 1; } void fix(vector<int> &v) { int dup = -1, n = v.size(); for (int i = n - 1; i > 0; i--) { if (v[i] == v[i - 1]) { dup = i - 1; break; } } if (~dup) { int id = n - 1; while (id >= dup + 2) { ans.push_back(id - 2); tros(id - 2, v); id -= 2; } ans.push_back(dup); tros(dup, v); } } void fix2(vector<int> &v) { int dup = -1, n = v.size(); for (int i = n - 1; i > 0; i--) { if (v[i] == v[i - 1]) { dup = i - 1; break; } } if (~dup) { int id = n - 1; while (id >= dup + 2) { ans.push_back(id - 2); tros(id - 2, v); id -= 2; } ans.push_back(dup); tros(dup, v); ans.push_back(dup); tros(dup, v); } } void fix3(vector<int> &v) { int dup = -1, n = v.size(); for (int i = n - 1; i > 0; i--) { if (v[i] == v[i - 1]) { dup = i - 1; break; } } if (~dup) { int id = n - 1; while (id >= dup + 2) { ans.push_back(id - 2); tros(id - 2, v); id -= 2; } ans.push_back(dup); tros(dup, v); ans.push_back(dup); tros(dup, v); ans.push_back(dup); tros(dup, v); } } int main() { int t; cin >> t; while (t--) { int n, mx = 0, id = -1; cin >> n; vector<int> v(n); for (int i = 0; i < n; i++) { cin >> v[i]; if (v[i] > mx) mx = v[i], id = i; } sort(v); if (!sorted(v)) fix(v), sort(v); if (v[n - 1] == v[n - 3] and v[n - 2] > v[n - 1]) { ans.push_back(n - 3); tros(n - 3, v); } if (sorted(v)) { cout << ans.size() << endl; assert(ans.size() <= n * n); for (int i : ans) cout << i + 1 << ' '; cout << endl; } else cout << -1 << endl; ans.clear(); } }
#include <bits/stdc++.h> const int N = 502; void sw(float* x) { float tmp = *x; *x = *(x + 2); *(x + 2) = *(x + 1); *(x + 1) = tmp; } int main() { int _t; scanf("%d", &_t); while (_t--) { static float arr[N]; static int anss[N * N]; static int tm[N]; memset(tm, 0, sizeof(tm)); int n; scanf("%d", &n); int f2 = -1; for (int i = 1; i <= n; i++) { int a; scanf("%d", &a); tm[a]++; if (tm[a] == 2) f2 = a; arr[i] = a + 0.0001 * tm[a]; } int nx = 0; for (int i = 1; i < n; i++) for (int j = i + 1; j <= n; j++) if (arr[i] > arr[j]) nx++; if (nx & 1) { if (f2 != -1) { int f21 = -1, f22 = -1; for (int i = 1; i <= n; i++) if (((int)arr[i]) == f2) { if (f21 == -1) f21 = i; else if (f22 == -1) f22 = i; else break; } std::swap(arr[f21], arr[f22]); nx++; } else { printf("-1\n"); continue; } } int ans = 0; while (nx) { for (int i = 1; i <= n - 2; i++) { if (arr[i] < arr[i + 2] && arr[i + 2] < arr[i + 1] || arr[i] > arr[i + 2] && arr[i + 2] > arr[i + 1]) { sw(arr + i); anss[++ans] = i; } if (arr[i] < arr[i + 1] && arr[i] > arr[i + 2] || arr[i] > arr[i + 1] && arr[i + 1] > arr[i + 2]) { sw(arr + i); nx -= 2; anss[++ans] = i; } } } printf("%d\n", ans); for (int i = 1; i <= ans; i++) printf("%d ", anss[i]); printf("\n"); } return 0; }
#include <bits/stdc++.h> using namespace std; long long MOD(long long x, long long m) { long long r = x % m; if (r < 0) { r += m; } return r; } ostream& operator<<(ostream& str, const pair<long long, long long>& p) { str << p.first << " " << p.second; return str; } template <typename T> void join(T& arr, string sep) { bool first = true; for (auto t : arr) { if (first) { first = false; cout << t; } else { cout << sep << t; } } cout << "\n"; } void solve() { long long n; cin >> n; vector<long long> a(n); for (long long i = 0; i < (long long)(n); ++i) { cin >> a[i]; } function<bool(long long)> tswap = [&](long long i) { long long mx = max(a[i], a[i + 1]); mx = max(mx, a[i + 2]); if (a[i + 2] == mx) { return false; } swap(a[i + 2], a[i + 1]); swap(a[i + 1], a[i]); return true; }; vector<long long> ops; bool move = true; while (move) { move = false; for (long long i = (long long)(0); i < (long long)(n - 2); ++i) { if (tswap(i)) { move = true; ops.push_back(i + 1); if (tswap(i)) ops.push_back(i + 1); } } } if (a[0] > a[1] && a[0] != a[2]) { long long i = 1; while (i < n - 1) { if (a[i] == a[i + 1]) break; i++; } if (i == n - 1) { cout << "-1\n"; return; } i--; while (i >= 0) { swap(a[i + 2], a[i + 1]); swap(a[i + 1], a[i]); ops.push_back(i + 1); i--; } } if (a[0] == a[2]) { ops.push_back(1); ops.push_back(1); } cout << ops.size() << "\n"; join(ops, " "); } int main() { ios::sync_with_stdio(false); cin.tie(0); int tt = 1; cin >> tt; for (int t = 1; t <= tt; t++) { solve(); } return 0; }
#include <bits/stdc++.h> using namespace std; const int N = 510; vector<int> ans; int a[N]; int n; void move(int x, int t) { while (t--) { ans.push_back(x); int tmp = a[x + 2]; a[x + 2] = a[x + 1]; a[x + 1] = a[x]; a[x] = tmp; } if (0) for (int i = 1; i <= n; ++i) printf("%d%c", a[i], " \n"[i == n]); } int main() { int T; scanf("%d", &T); while (T--) { scanf("%d", &n); for (int i = 1; i <= n; ++i) scanf("%d", a + i); int tot = 0; ans.clear(); bool flag = true; for (; tot < n;) { int num = 1e9; for (int i = tot + 1; i <= n; ++i) num = min(num, a[i]); if (0) printf("deal %d:\n", num); for (int i = tot + 1; i <= n; ++i) { if (a[i] != num) continue; if (0) printf("found a[%d]=%d\n", i, a[i]); tot++; if ((i - tot) % 2 == 0) { for (int j = i; j - 2 >= tot; j -= 2) move(j - 2, 1); continue; } if (tot >= 2 && a[tot - 1] == num) { for (int j = i; j - 2 >= tot; j -= 2) move(j - 2, 1); move(tot - 1, 1); continue; } if (tot + 1 < n) { for (int j = i; j - 2 >= tot; j -= 2) move(j - 2, 1); move(tot, 2); continue; } int same = n - 2; for (; same > 1 && a[same] != a[same - 1]; --same) ; if (same <= 1) { flag = false; break; } int rep = (tot - same) % 2 == 0 ? tot : n; for (int j = rep; j - 2 >= same; j -= 2) move(j - 2, 1); move(same - 1, 1); for (int j = same + 1; j + 2 <= n; j += 2) move(j, 2); } } if (!flag) puts("-1"); else { int ans_size = ans.size(); printf("%d\n", ans_size); for (int i = 0; i < ans_size; ++i) printf("%d%c", ans[i], " \n"[i == ans_size - 1]); if (ans_size == 0) puts(""); } } return 0; }
#include <bits/stdc++.h> using namespace std; mt19937 gen(time(0)); bool IS_ONE_TEST = 0; vector<int> res; int total = 0; bool proc(int idx, vector<int> &a) { if (!total) return 0; res.push_back(idx + 1); int temp = a[idx + 2]; a[idx + 2] = a[idx + 1]; a[idx + 1] = a[idx]; a[idx] = temp; --total; return 1; } void solve() { int n; cin >> n; res.clear(); vector<int> a(n); for (int i = 0; i < n; ++i) cin >> a[i]; vector<int> b = a; total = n * n; sort(a.begin(), a.end()); for (int z = 0; z < n; ++z) { for (int i = 0; i + 2 < n; ++i) { int mn = min({b[i], b[i + 1], b[i + 2]}); while (b[i] != mn && proc(i, b)) { } } for (int i = n - 1; i > 1; --i) { int mx = max({b[i], b[i - 1], b[i - 2]}); while (b[i] != mx && proc(i - 2, b)) { } } } if (a == b) { cout << res.size() << endl; for (auto &c : res) cout << c << " "; cout << endl; } else cout << -1 << endl; } int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL); cout << fixed << setprecision(15); int t; if (IS_ONE_TEST) t = 1; else cin >> t; while (t-- > 0) { solve(); } }
#include <bits/stdc++.h> using namespace std; const int maxn = 555; int ori[maxn]; vector<int> ans; int n; inline void show() { for (int i = 1; i <= n; i++) cout << ori[i] << " "; cout << endl; } inline void move(int x) { if (ans.size() >= 2 && ans[ans.size() - 1] == x && ans[ans.size() - 2] == x) { ans.pop_back(); ans.pop_back(); } else ans.push_back(x); int temp = ori[x + 2]; ori[x + 2] = ori[x + 1]; ori[x + 1] = ori[x]; ori[x] = temp; } void go(int head, int pos) { while (head <= pos - 2) { move(pos - 2); pos -= 2; } while (head < pos) { move(pos - 1); move(pos - 1); pos--; } } void gor(int head, int pos) { while (pos < head) { move(pos); move(pos); pos += 2; } } void solve() { ans.clear(); scanf("%d", &n); for (int i = 1; i <= n; i++) scanf("%d", &ori[i]); for (int head = 1; head <= n - 2; head++) { int pos = head; for (int i = head + 1; i <= n; i++) { if (ori[pos] > ori[i]) pos = i; } go(head, pos); } if (ori[n - 1] > ori[n]) { if (ori[n] == ori[n - 2]) go(n - 2, n); else { int head = -1; for (int i = 2; i <= n - 2; i++) { if (ori[i - 1] == ori[i]) { head = i; break; } } if (head == -1) { puts("-1"); return; } if ((n - head) % 2 == 0) { go(head, n); move(head - 1); move(head - 1); gor(n - 1, head - 1); } else { go(head, n - 1); move(head - 1); gor(n, head + 1); } } } cout << ans.size() << endl; for (int aa : ans) cout << aa << " "; cout << endl; } signed main() { int T; cin >> T; while (T--) solve(); }
#include <bits/stdc++.h> using namespace std; const int MAXN = 500; const int INF = 1e9; int n, a[MAXN + 5], ans[MAXN * MAXN + 5], cnt_ans; void work(int i) { assert(i <= n - 2); ans[++cnt_ans] = i; int x = a[i]; int y = a[i + 1]; int z = a[i + 2]; a[i] = z; a[i + 1] = x; a[i + 2] = y; } void print_ans() { cout << cnt_ans << endl; for (int i = 1; i <= cnt_ans; ++i) cout << ans[i] << " "; cout << endl; } void fail() { cout << -1 << endl; } void solve(int st) { for (int i = st; i <= n - 2; ++i) { int minval = INF, minpos = 0; for (int j = i; j <= n; ++j) { if (a[j] < minval) { minval = a[j]; minpos = j; } } if (minpos == i) continue; if ((minpos - i) % 2 == 0) { for (int j = minpos - 2; j >= i; j -= 2) { work(j); } assert(a[i] == minval); } else { if (minpos > n - 2) { if (minpos == i + 1) { work(i); work(i); continue; } work(minpos - 2); minpos -= 2; } work(minpos); for (int j = minpos - 1; j >= i; j -= 2) { work(j); } assert(a[i] == minval); } } } int main() { int T; cin >> T; while (T--) { cin >> n; for (int i = 1; i <= n; ++i) cin >> a[i]; cnt_ans = 0; solve(1); if (a[n - 1] > a[n]) { if (a[n - 2] == a[n - 1] || a[n - 2] == a[n]) { work(n - 2); print_ans(); continue; } bool ok = 0; for (int i = n - 3; i >= 1; --i) { if (a[i] == a[i + 1]) { work(i + 1); work(i); solve(i + 2); ok = 1; break; } } if (!ok) fail(); else print_ans(); } else print_ans(); } return 0; }
#include <bits/stdc++.h> using i32 = int; using i64 = long long; i32 main() { std::ios::sync_with_stdio(false); std::cout.tie(nullptr); std::cin.tie(nullptr); i32 T; std::cin >> T; while (T--) { i32 n; std::cin >> n; std::vector<i32> a(n); for (i32 i = 0; i < n; i++) std::cin >> a[i]; std::vector<i32> ans; auto flip = [&](i32 i) { std::swap(a[i], a[i + 2]); std::swap(a[i + 1], a[i + 2]); ans.push_back(i + 1); }; for (i32 i = 0; i + 2 < n; i++) { i32 j = std::min_element(a.begin() + i, a.end()) - a.begin(); for (; 1 < j - i; j -= 2) flip(j - 2); if (j - i == 1) { flip(i); flip(i); } } if (a[n - 1] < a[n - 2]) { i32 i = 1; while (i + 2 < n && a[i - 1] != a[i]) i++; if (i + 2 == n) { if (a[n - 3] != a[n - 1]) { std::cout << "-1\n"; continue; } flip(n - 3); } else { flip(i - 1); flip(i - 1); flip(i); flip(i++); for (; i + 2 < n; i++) { flip(i); flip(i); } } } assert(std::is_sorted(a.begin(), a.end())); std::cout << ans.size() << "\n"; for (i32 i = 0; i < ans.size(); i++) std::cout << ans[i] << " \n"[i + 1 == ans.size()]; } return 0; }
#include <bits/stdc++.h> #pragma GCC optimize("Ofast") using namespace std; using ll = long long; using ull = unsigned long long; using ld = long double; template <typename T> using mat = vector<vector<T>>; template <int mod> struct modint { int x; modint() : x(0) {} modint(int64_t y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {} modint &operator+=(const modint &p) { if ((x += p.x) >= mod) x -= mod; return *this; } modint &operator-=(const modint &p) { if ((x += mod - p.x) >= mod) x -= mod; return *this; } modint &operator*=(const modint &p) { x = (int)(1LL * x * p.x % mod); return *this; } modint &operator/=(const modint &p) { *this *= p.inverse(); return *this; } modint operator-() const { return modint(-x); } modint operator+(const modint &p) const { return modint(*this) += p; } modint operator-(const modint &p) const { return modint(*this) -= p; } modint operator*(const modint &p) const { return modint(*this) *= p; } modint operator/(const modint &p) const { return modint(*this) /= p; } bool operator==(const modint &p) const { return x == p.x; } bool operator!=(const modint &p) const { return x != p.x; } modint inverse() const { int a = x, b = mod, u = 1, v = 0, t; while (b > 0) { t = a / b; swap(a -= t * b, b); swap(u -= t * v, v); } return modint(u); } modint pow(int64_t n) const { modint ret(1), mul(x); while (n > 0) { if (n & 1) ret *= mul; mul *= mul; n >>= 1; } return ret; } friend ostream &operator<<(ostream &os, const modint &p) { return os << p.x; } friend istream &operator>>(istream &is, modint &a) { int64_t t; is >> t; a = modint<mod>(t); return (is); } static int get_mod() { return mod; } }; ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; } ll lcm(ll a, ll b) { return a / gcd(a, b) * b; } template <class T> bool chmax(T &a, const T &b) { if (a < b) { a = b; return 1; } return 0; } template <class T> bool chmin(T &a, const T &b) { if (b < a) { a = b; return 1; } return 0; } template <typename T> T mypow(T x, ll n) { T ret = 1; while (n > 0) { if (n & 1) (ret *= x); (x *= x); n >>= 1; } return ret; } ll modpow(ll x, ll n, const ll mod) { ll ret = 1; while (n > 0) { if (n & 1) (ret *= x); (x *= x); n >>= 1; x %= mod; ret %= mod; } return ret; } uint64_t my_rand(void) { static uint64_t x = 88172645463325252ULL; x = x ^ (x << 13); x = x ^ (x >> 7); return x = x ^ (x << 17); } ll popcnt(ull x) { return __builtin_popcountll(x); } template <typename T> struct edge { int src, to; T cost; edge(int to, T cost) : src(-1), to(to), cost(cost) {} edge(int src, int to, T cost) : src(src), to(to), cost(cost) {} edge &operator=(const int &x) { to = x; return *this; } bool operator<(const edge<T> &r) const { return cost < r.cost; } operator int() const { return to; } }; template <typename T> using Edges = vector<edge<T>>; template <typename T> using WeightedGraph = vector<Edges<T>>; using UnWeightedGraph = vector<vector<int>>; struct Timer { clock_t start_time; void start() { start_time = clock(); } int lap() { return (clock() - start_time) * 1000 / CLOCKS_PER_SEC; } }; const long double eps = 0.000001; const long double PI = 3.141592653589793; template <typename T> struct BIT { vector<T> data; BIT(int sz) { data.assign(++sz, 0); } T sum(int k) { T ret = 0; for (; k > 0; k -= k & -k) ret += data[k]; return (ret); } void add(int k, T x) { for (++k; k < data.size(); k += k & -k) data[k] += x; } int search(long long k) { ++k; int res = 0; int N = 1; while (N < (int)data.size()) N *= 2; for (int i = N / 2; i > 0; i /= 2) { if (res + i < (int)data.size() && data[res + i] < k) { k = k - data[res + i]; res = res + i; } } return res; } void show() { for (ll i = (0), max_i = (((ll)(data).size()) - 1); i < max_i; i++) cout << sum(i + 1) - sum(i) << ' '; cout << '\n'; } }; ll inversion_number(vector<int> &x, int n) { BIT<int> bit(n); ll res = 0; for (int &y : x) { res += bit.sum(n - 1 - y); bit.add(n - 1 - y, 1); } return res; } void move(vector<int> &x, vector<int> &y, int i) { assert(x.size() - 2 > i); int a = x[i], b = x[i + 1], c = x[i + 2]; swap(y[a], y[b]); swap(y[c], y[b]); swap(x[i + 2], x[i + 1]); swap(x[i], x[i + 1]); } void solve() { int n; cin >> n; vector<int> a(n); vector<pair<int, int>> inv(n); for (ll i = (0), max_i = (n); i < max_i; i++) cin >> a[i], inv[i] = make_pair(a[i], i); sort((inv).begin(), (inv).end()); vector<int> id(n); for (ll i = (0), max_i = (n); i < max_i; i++) id[i] = inv[i].second; int num = inversion_number(id, n); if (num % 2 == 1) { bool flag = false; for (ll i = (0), max_i = (n - 1); i < max_i; i++) { if (inv[i].first == inv[i + 1].first) { swap(inv[i].second, inv[i + 1].second); swap(id[i], id[i + 1]); flag = true; break; } } if (not flag) { cout << -1 << '\n'; return; } } vector<int> now(n), now_inv(n); iota((now).begin(), (now).end(), 0); iota((now_inv).begin(), (now_inv).end(), 0); vector<int> ans; for (ll i = (0), max_i = (n); i < max_i; i++) { int a = id[i]; while (now_inv[a] != i) { if (now_inv[a] == n - 1) { ans.push_back(now_inv[a] - 1); move(now, now_inv, now_inv[a] - 2); continue; } int tmp = now_inv[a] - 1; ans.push_back(tmp + 1); ans.push_back(tmp + 1); move(now, now_inv, tmp); move(now, now_inv, tmp); } } cout << ans.size() << '\n'; for (ll i = (0), max_i = (ans.size()); i < max_i; i++) cout << ans[i] << ' '; cout << '\n'; } int main() { cin.tie(0); ios::sync_with_stdio(0); cout << setprecision(20); int t; cin >> t; for (ll _ = (0), max_i = (t); _ < max_i; _++) { solve(); } }
#include <bits/stdc++.h> using namespace std; long long int power(long long int x, long long int y) { long long int res = 1; while (y) { if (y % 2) res = (res * x) % 998244353; y /= 2; x = (x * x) % 998244353; } return res; } void cycshift(long long int pos, long long int* a) { long long int temp = a[pos]; a[pos] = a[pos + 2]; a[pos + 2] = a[pos + 1]; a[pos + 1] = temp; } int main() { long long int t, i, j, n; cin >> t; while (t--) { cin >> n; long long int a[n]; vector<long long int> v; for (i = 0; i < n; i++) { cin >> a[i]; } for (i = 0; i < n; i++) { long long int mn = 1000000000000, pos = -1; for (j = i; j < n; j++) { if (mn > a[j]) { mn = a[j]; pos = j; } } if ((pos - i) == 1 && pos == n - 1) break; for (j = pos - 2; j >= i; j -= 2) { v.push_back(j); cycshift(j, a); } if ((pos - i) % 2) { for (j = 0; j < 2; j++) { v.push_back(i); cycshift(i, a); } } } long long int z = -1; if (a[n - 3] == a[n - 1]) { cycshift(n - 3, a); v.push_back(n - 3); i = n - 1; } for (j = 0; j < n - 1; j++) if (a[j] == a[j + 1]) z = j; if (i < n - 1 && z == -1) cout << -1 << endl; else { if (i == n - 2) { for (j = n - 3; j >= z; j -= 2) { cycshift(j, a); v.push_back(j); } cycshift(z, a); v.push_back(z); if ((n - 1 - z) % 2) z++; for (i = z + 1; i <= n - 4; i += 2) { for (j = 0; j < 2; j++) { v.push_back(i); cycshift(i, a); } } } cout << v.size() << endl; for (j = 0; j < v.size(); j++) cout << v[j] + 1 << " "; cout << endl; } } return 0; }
#include <bits/stdc++.h> using namespace std; #pragma GCC optimize("O3") #pragma GCC optimize("Ofast") #pragma GCC optimize("unroll-loops") const long long inf = 1e18; long long i, j, k, n, m, x, y, ma = -inf, mi = inf, qq = 1, w, frr, to, t, ppp; char ch; vector<long long> a; void solve() { cin >> n; a.resize(n); vector<pair<long long, long long> > b(n); for (i = 0; i < n; i++) { cin >> a[i]; b[i] = {a[i], i}; } sort((b).begin(), (b).end()); long long cnt = -1; for (i = 0; i < n; i++) { if (i == 0 || b[i].first != b[i - 1].first) cnt++; a[b[i].second] = cnt; } for (i = 0; i < n; i++) { b[i].first = a[i]; } sort((b).begin(), (b).end()); vector<long long> ans; long long t1, t2, t3; for (i = 0; i < n - 2; i++) { if (a[i] == b[i].first) continue; long long it; for (j = i + 1; j < n; j++) if (a[j] == b[i].first) { it = j; break; } while (it - i > 1) { ans.push_back(it - 2); t1 = a[it - 2]; t2 = a[it - 1]; t3 = a[it]; a[it] = t2; a[it - 1] = t1; a[it - 2] = t3; it -= 2; } if (it != i) { ans.push_back(i); ans.push_back(i); swap(a[i], a[i + 2]); swap(a[i], a[i + 1]); } } if (a[n - 1] == a[n - 3]) { ans.push_back(n - 3); swap(a[n - 2], a[n - 1]); } if (a[n - 1] == b[n - 1].first) { cout << ans.size() << '\n'; for (auto v : ans) cout << v + 1 << ' '; cout << '\n'; } else { if (cnt == n - 1 || n < 4) { cout << "-1\n"; return; } long long it; for (i = n - 3; i > 0; i--) { if (b[i].first == b[i - 1].first) { it = i - 1; break; } } long long fit = it; while (it < n - 4) { ans.push_back(it); swap(a[it], a[it + 2]); it++; } ans.push_back(n - 4); ans.push_back(n - 4); ans.push_back(n - 3); ans.push_back(n - 3); it = n - 5; while (it >= fit) { ans.push_back(it); ans.push_back(it); it--; } cout << ans.size() << '\n'; for (auto v : ans) cout << v + 1 << ' '; cout << '\n'; } } int32_t main() { ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr); cin >> qq; while (qq--) { solve(); } }
#include <bits/stdc++.h> using namespace std; using namespace std::chrono; template <typename A> ostream &operator<<(ostream &cout, vector<A> const &v); template <typename A, typename B> ostream &operator<<(ostream &cout, pair<A, B> const &p) { return cout << "(" << p.first << ", " << p.second << ")"; } template <typename A> ostream &operator<<(ostream &cout, vector<A> const &v) { cout << "["; for (int i = 0; i < v.size(); i++) { if (i) cout << ", "; cout << v[i]; } return cout << "]"; } template <typename A, typename B> istream &operator>>(istream &cin, pair<A, B> &p) { cin >> p.first; return cin >> p.second; } mt19937 rng(61378913); void usaco(string filename) { freopen((filename + ".in").c_str(), "r", stdin); freopen((filename + ".out").c_str(), "w", stdout); } const long double pi = 3.14159265358979323846; const long long mod = 1000000007; long long n, m, k, q, l, r, x, y, z; long long a[1000005]; long long b[1000005]; long long c[1000005]; string second, t; long long ans = 0; void cyc(long long pos) { b[pos + 1] = a[pos]; b[pos + 2] = a[pos + 1]; b[pos] = a[pos + 2]; for (long long i = (pos); i < (pos + 3); ++i) a[i] = b[i]; } void solve(int tc) { cin >> n; for (int ele = 0; ele < n; ele++) cin >> a[ele]; ; vector<long long> ops; for (long long i = 0; i < (n + 5); ++i) { if (i == n + 1) { long long p = -1; for (long long i = (3); i < (n - 1); ++i) if (a[i] == a[i + 1]) { p = i; break; } if (p != -1) { --p; while (p >= 3) { for (long long i = 0; i < (2); ++i) { ops.push_back(p + 1); cyc(p); } --p; } for (long long i = 0; i < (2); ++i) { ops.push_back(2); cyc(1); } for (long long i = 0; i < (2); ++i) { ops.push_back(3); cyc(2); } p = 3; while (p + 2 < n) { if (a[p + 1] <= a[p + 2]) break; ops.push_back(p + 1); cyc(p); ++p; } } else { if (n > 3) { for (long long i = 0; i < (3); ++i) if (a[i] == a[3]) { for (long long j = 0; j < (2 - i); ++j) { ops.push_back(1); cyc(0); } for (long long i = 0; i < (2); ++i) { ops.push_back(1); cyc(0); } for (long long i = 0; i < (2); ++i) { ops.push_back(2); cyc(1); } break; } } } } long long wpos = -1; for (long long j = (n - 2); j >= 0; --j) { if (a[j] > a[j + 1]) { if (wpos == -1 || a[j] > a[wpos]) wpos = j; } } if (wpos == -1) break; long long st = wpos - 1; if (st == -1) { ops.push_back(1); cyc(0); st = 0; } while (st + 1 < n - 1) { if (a[st + 1] <= a[st + 2]) break; ops.push_back(st + 1); cyc(st); ++st; } } if (((long long)ops.size()) > n * n) { cout << -1 << '\n'; return; } bool is = 1; for (long long i = 0; i < (n - 1); ++i) if (a[i] > a[i + 1]) is = 0; if (!is) { cout << -1 << '\n'; } else { cout << ops.size() << '\n'; { for (int ele = 0; ele < (ops.size()); ele++) { if (ele) cout << " "; cout << ops[ele]; } cout << '\n'; }; } } int main() { { ios_base::sync_with_stdio(false); } { cin.tie(NULL); cout.tie(NULL); } int tc = 1; cin >> tc; for (int t = 0; t < tc; t++) solve(t); }
#include <bits/stdc++.h> using namespace std; vector<int> v, ans; void op(int i) { int x = v[i + 2]; v[i + 2] = v[i + 1]; v[i + 1] = v[i]; v[i] = x; if (ans.size() >= 2 && ans[ans.size() - 1] == i + 1 && ans[ans.size() - 2] == i + 1) ans.pop_back(), ans.pop_back(); else ans.push_back(i + 1); } void reach(int x, int y) { while (y > x + 1) op(y - 2), y -= 2; if (y == x + 1) op(y - 1), op(y - 1); } int main(int argc, char **argv) { ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); int t; cin >> t; while (t--) { int n, st = 0, temp = 0; ans.clear(); cin >> n; v.resize(n); vector<int> ar(501, -1); int val = -1, x, y; for (int i = 0; i < n; i++) { cin >> v[i]; if (ar[v[i]] != -1) val = v[i], x = ar[v[i]], y = i; ar[v[i]] = i; } if (val != -1) v[x] = v[y] = 2000; while (n - st > 3) { int mi = 1000, in; for (int j = st; j < n; j++) if (v[j] < mi) mi = v[j], in = j; reach(st, in); st++; } if (val == -1) { while (!(v[st] <= v[st + 1] && v[st + 1] <= v[st + 2])) { op(st), temp++; if (temp > 5) { cout << -1 << endl; goto brk; } } } else { while (v[st + 1] != 2000 || v[st + 2] != 2000) op(st); while (st >= 0 && val < v[st]) op(st), op(st), st--; } cout << ans.size() << endl; for (auto x : ans) cout << x << " "; cout << endl; brk:; } }
#include <bits/stdc++.h> using namespace std; int a[512]; int main() { int n, t; scanf("%d", &t); while (t--) { scanf("%d", &n); for (int i = 1; i <= n; i++) scanf("%d", &a[i]); vector<int> ans; for (int i = 1; i <= n; i++) { for (int j = 1; j < n - 1; j++) { if (a[j] > a[j + 1]) { swap(a[j], a[j + 2]); swap(a[j], a[j + 1]); ans.emplace_back(j); ans.emplace_back(j); } else if (a[j + 1] > a[j + 2]) { swap(a[j], a[j + 1]); swap(a[j], a[j + 2]); ans.emplace_back(j); } } } int i; for (i = 2; i <= n; i++) if (a[i] < a[i - 1]) break; if (i <= n) printf("-1\n"); else { printf("%d\n", ans.size()); for (int x : ans) printf("%d ", x); ; printf("\n"); } } return 0; }
#include <bits/stdc++.h> using namespace std; const int M = 110000; const unsigned long long inf = 9e18; int n, m, k; int a[M]; int cal(int s) { int p = s; for (int i = (s + 1); i <= (n); ++i) if (a[i] < a[p]) p = i; return p; } vector<int> ans; void mv(int x) { int t = a[x]; a[x] = a[x + 2]; a[x + 2] = a[x + 1]; a[x + 1] = t; ans.push_back(x); } int b[555]; void solve() { ans.clear(); int num[555] = {0}; cin >> n; for (int i = (1); i <= (n); ++i) { cin >> a[i]; b[i] = a[i]; } sort(b + 1, b + 1 + n); for (int i = (1); i <= (n); ++i) { int pos = lower_bound(b + 1, b + 1 + n, a[i]) - b; a[i] = pos + num[pos]; ++num[pos]; } int inv = 0; for (int i = (1); i <= (n); ++i) { for (int j = (i + 1); j <= (n); ++j) { if (a[j] < a[i]) ++inv; } } if (inv & 1) { for (int i = (1); i <= (n - 1); ++i) { if (b[i] == b[i + 1]) { for (int j = (1); j <= (n); ++j) { if (a[j] == i) ++a[j]; else if (a[j] == i + 1) --a[j]; } break; } } } for (int c = (1); c <= (n - 2); ++c) { int t = cal(c); while (t > c + 1) { t -= 2; mv(t); } if (t > c) { mv(c); mv(c); } } if (a[n - 1] > a[n]) cout << -1 << endl; else { cout << (ans.size()) << endl; for (int x : ans) cout << x << ' '; puts(""); } } int main() { int t; cin >> t; while (t--) { solve(); } return 0; }
#include <bits/stdc++.h> using namespace std; const int inf = 0x3f3f3f3f; const long long mod = 1000000007; const long long linf = 0x3f3f3f3f3f3f3f3f; const int N = 300100; mt19937 rng(chrono::steady_clock::now().time_since_epoch().count()); void bubsort(vector<int>& a, int i) { swap(a[i + 1], a[i + 2]); swap(a[i], a[i + 1]); } void solve() { int n; cin >> n; vector<int> a(n); vector<pair<int, int> > v(n); for (int i = 0; i < n; i++) { cin >> a[i]; v[i] = {a[i], i}; } sort(v.begin(), v.end()); for (int i = 0; i < n; i++) { a[v[i].second] = i; } int inv = 0; for (int i = 0; i < n; i++) { for (int j = i + 1; j < n; j++) { inv += a[i] > a[j]; } } if (inv & 1) { for (int i = 0; i < n - 1; i++) { if (v[i].first == v[i + 1].first) { swap(a[v[i].second], a[v[i + 1].second]); break; } } } vector<int> ans; for (int i = 0; i < n - 2; i++) { int ind = -1; int mx = n; for (int j = i; j < n; j++) { if (mx > a[j]) mx = a[j], ind = j; } while (ind > i + 1) { ind -= 2; bubsort(a, ind); ans.push_back(ind); } if (ind == i + 1) { bubsort(a, i); bubsort(a, i); ans.push_back(i); ans.push_back(i); } } for (int i = 0; i < 3; i++) { if (is_sorted(a.begin(), a.end())) { break; } bubsort(a, n - 3); ans.push_back(n - 3); } if (!is_sorted(a.begin(), a.end())) cout << "-1\n"; else { cout << int(ans.size()) << "\n"; for (auto p : ans) cout << p + 1 << " "; cout << "\n"; } } int32_t main() { cin.tie(0)->sync_with_stdio(0); ; int t_ = 1; cin >> t_; while (t_--) solve(); return 0; }
#include <bits/stdc++.h> using namespace std; int main() { int T; scanf("%d", &T); while (T--) { int n; cin >> n; vector<int> a(n); for (int &t : a) cin >> t; vector<int> ans; auto apply_rot = [&](int id) { rotate(a.begin() + id, a.begin() + id + 2, a.begin() + id + 3); ans.push_back(id); }; for (int i = 0; i + 2 < n; i++) { int p = min_element(a.begin() + i, a.end()) - a.begin(); int v = a[p]; for (; p >= i + 2; p -= 2) { apply_rot(p - 2); } while (a[i] != v) apply_rot(i); } if (a[n - 2] > a[n - 1]) { for (int i = n - 1; i > 0; i--) { if (a[i] == a[i - 1]) { int v = a[i]; for (int j = i; j + 2 < n; j += 2) { while (a[j + 2] != v) apply_rot(j); } int p = n - 1; if (a[n - 1] != v) apply_rot(n - 3); else { apply_rot(n - 3); apply_rot(n - 3); p = n - 2; } for (; p >= i + 2; p -= 2) { apply_rot(p - 2); } if (p != i) { apply_rot(p - 2); } break; } } } if (a[n - 3] == a[n - 1]) apply_rot(n - 3); if (is_sorted(begin(a), end(a))) { cout << int(ans.size()) << endl; for (int t : ans) cout << t + 1 << " "; cout << endl; } else { puts("-1"); } } }
#include <bits/stdc++.h> using namespace std; const int N = 501; int a[N]; int as[N * N], ac = 0; void f(int i) { as[++ac] = i; swap(a[i], a[i + 1]); swap(a[i], a[i + 2]); } int main(void) { int T; scanf("%d", &T); while (T--) { int n; scanf("%d", &n); for (int i = 1; i <= n; ++i) scanf("%d", &a[i]); bool fail = 0; int p = 0; for (int i = 1; i <= n; ++i) { int j = min_element(a + i, a + n + 1) - a; while (j > i + 1) f(j - 2), j -= 2; if (j == i + 1) { if (j <= n - 1) f(i), f(i); else if (p) { f(p - 1), f(p - 1), i = p - 1; } else { f(i - 1); if (!is_sorted(a + i - 1, a + n + 1)) { ac = -1; break; } } } if (a[i] == a[i - 1]) p = i; } printf("%d\n", ac); if (ac == 0) printf("\n"); if (ac > 0) for (int i = 1; i <= ac; ++i) printf("%d%c", as[i], " \n"[i == ac]); ac = 0; } return 0; }
#include <bits/stdc++.h> using namespace std; const long long MAX = 1e6 + 8; const long long MOD = 1e9 + 7; const long long sz = 1e5 + 5; void f_io() { ios::sync_with_stdio(0); cin.tie(0); cout.tie(0); ; } int32_t main() { f_io(); long long tc = 1; cin >> tc; auto rotate = [](vector<long long> &arr, long long index) { swap(arr[index], arr[index + 1]); swap(arr[index], arr[index + 2]); }; while (tc--) { long long n; cin >> n; vector<long long> v(n); vector<long long> ret; for (auto &el : v) cin >> el; for (long long i = 0; i < n; i++) { for (long long j = 0; j < n - 2; j++) { if (v[j] > v[j + 1]) { rotate(v, j); rotate(v, j); ret.push_back(j); ret.push_back(j); } else if (v[j + 1] > v[j + 2]) { rotate(v, j); ret.push_back(j); } } } if (!is_sorted(begin(v), end(v))) cout << "-1" << "\n"; else { cout << ret.size() << "\n"; for (auto el : ret) cout << el + 1 << " "; cout << "\n"; } } }
#include <bits/stdc++.h> int ans[252000], a[510], tot; void move(int u) { int t1, t2, t3; t1 = a[u], t2 = a[u + 1], t3 = a[u + 2]; a[u] = t3, a[u + 1] = t1, a[u + 2] = t2; } int main() { int t, n, i, j, mn, mx, u; scanf("%d", &t); while (t--) { tot = 0; scanf("%d", &n); for (i = 1; i <= n; i++) scanf("%d", &a[i]); for (i = 1; i <= n - 2; i++) { mn = 1000; for (j = i; j <= n; j++) if (a[j] < mn) mn = a[j], u = j; while (u >= i + 2) ans[++tot] = u - 2, move(u - 2), u -= 2; if (u == i + 1) move(i), move(i), ans[++tot] = i, ans[++tot] = i; } for (i = n; i >= 3; i--) { mx = -1; for (j = i; j >= 1; j--) if (a[j] > mx) mx = a[j], u = j; if (u <= i - 2) puts("0"); while (u <= i - 2) ans[++tot] = u, move(u), u += 2; if (u == i - 1) move(i - 2), ans[++tot] = i - 2; } for (i = 1; i < n; i++) if (a[i] > a[i + 1]) tot = -1; if (tot == -1) printf("-1\n"); else { printf("%d\n", tot); for (i = 1; i <= tot; i++) printf("%d ", ans[i]); printf("\n"); } } return 0; }
#include <bits/stdc++.h> using namespace std; template <typename Arg1> void __f(const char* name, Arg1&& arg1) { cout << name << " : " << arg1 << "\n"; } template <typename Arg1, typename... Args> void __f(const char* names, Arg1&& arg1, Args&&... args) { const char* comma = strchr(names + 1, ','); cout.write(names, comma - names) << " : " << arg1 << " | "; __f(comma + 1, args...); } inline long long sbt(long long x) { return __builtin_popcountll(x); } inline long long iceil(double a) { return (long long)(ceil(a)); } inline long long mul(long long a, long long b, long long m = (long long)(1e9 + 7)) { return ((a % m) * (b % m)) % m; } inline long long add(long long a, long long b, long long m = (long long)(1e9 + 7)) { return (a + b) % m; } inline long long sub(long long a, long long b, long long m = (long long)(1e9 + 7)) { return (a - b + m) % m; } long long fastpow(long long a, long long b, long long m = (long long)(1e9 + 7)) { long long res = 1; while (b > 0) { if (b & 1) res = mul(res, a, m); a = mul(a, a, m); b >>= 1; } return res; } long long modinv(long long a, long long m = (long long)(1e9 + 7)) { return fastpow(a, m - 2, m); } long long n; long long a[510], ranks[510]; vector<long long> v; long long count() { long long ct = 0; for (long i = 0; i < n; i++) { for (auto j = i + 1; j <= n - 1; j++) { if (ranks[i] > ranks[j]) { ct++; } } } return ct; } long long moves(long long i) { long long maxi = -1; for (auto j = i - 2; j <= i; j++) { maxi = max(maxi, ranks[j]); } long long c = 0, temp; while (ranks[i] != maxi) { v.push_back(i - 1); temp = ranks[i]; ranks[i] = ranks[i - 1]; ranks[i - 1] = ranks[i - 2]; ranks[i - 2] = temp; c++; } return c; } void get_ac() { v.clear(); cin >> n; set<long long> s; for (long i = 0; i < n; i++) { cin >> a[i]; s.insert(a[i]); } map<long long, vector<long long> > ind; for (long i = 0; i < n; i++) { ind[a[i]].push_back(i); } long long rank = 0; for (auto i : ind) { for (auto j : i.second) { ranks[j] = rank++; } } long long inv = count(); if (inv & 1) { bool f = 0; for (auto i : ind) { if ((long long)(i.second.size()) > 1) { swap(ranks[i.second[0]], ranks[i.second[1]]); f = 1; break; } } if (!f) { cout << -1; return; } } long long ans = 0; for (auto i = n - 1; i >= 2; i--) { for (auto j = 2; j <= i; j++) { long long c = moves(j); ans += c; } } if (ans <= n * n) { cout << ans; cout << "\n"; for (auto i : v) { cout << i << " "; } } else { cout << -1; } } int main() { cin.sync_with_stdio(false); cout.sync_with_stdio(false); cin.tie(NULL); long long testcases; cin >> testcases; while (testcases--) { get_ac(); cout << "\n"; } return 0; }
#include <bits/stdc++.h> using namespace std; long long int sqr(long long int x) { return x * x; } inline long long int add(long long int a, long long int b) { long long int c = a + b; if (c >= 1000000007) c -= 1000000007; return c; } inline long long int mul(long long int a, long long int b) { return (a * 1ll * b) % 1000000007; } inline long long int sub(long long int a, long long int b) { long long int c = a - b; if (c < 0) c += 1000000007; return c; } const int nax = 1000 * 1000 + 10; int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL); auto ok = [](vector<int> &v, int pos) { swap(v[pos + 1], v[pos + 2]); swap(v[pos], v[pos + 1]); }; int t; cin >> t; while (t--) { int n; cin >> n; vector<int> v(n); vector<pair<int, int>> x(n); for (int i = 0; i < n; ++i) { cin >> v[i]; x[i] = {v[i], i}; } sort(x.begin(), x.end()); for (int i = 0; i < n; ++i) { v[x[i].second] = i; } int cnt = 0; for (int i = 0; i < n; ++i) { for (int j = i + 1; j < n; ++j) { cnt += (v[j] < v[i]); } } if (cnt & 1) { for (int i = 0; i < n - 1; ++i) { if (x[i].first == x[i + 1].first) { swap(v[x[i].second], v[x[i + 1].second]); break; } } } vector<int> ans; for (int i = 0; i < n - 2; ++i) { int pos = min_element(v.begin() + i, v.end()) - v.begin(); while (pos > i + 1) { ok(v, pos - 2); ans.push_back(pos - 2); pos -= 2; } if (pos != i) { ok(v, i); ok(v, i); ans.push_back(i); ans.push_back(i); } } for (int i = 0; i < 3; ++i) { if (is_sorted(v.begin(), v.end())) break; ok(v, n - 3); ans.push_back(n - 3); } if (!is_sorted(v.begin(), v.end())) { cout << -1 << "\n"; } else { cout << ans.size() << "\n"; for (int i = 0; i < ans.size(); ++i) cout << ans[i] + 1 << " "; cout << "\n"; } } return 0; }
#include <bits/stdc++.h> using namespace std; inline int read() { int x = 0, f = 1; char c = getchar(); while (c < '0' || c > '9') { if (c == '-') f = -1; c = getchar(); } while (c >= '0' && c <= '9') { x = (x << 3) + (x << 1) + (c ^ 48); c = getchar(); } return f == 1 ? x : -x; } inline void print(int x) { if (x < 0) x = ~x + 1, putchar('-'); if (x >= 10) print(x / 10); putchar((x % 10) | 48); } int T; int n; int a[510]; int pos[510]; struct node { int val, id; } b[510]; bool cmp(node x, node y) { return x.val == y.val ? x.id < y.id : x.val < y.val; } int m; int ans[250010]; map<int, int> vis; int main() { T = read(); while (T--) { n = read(); m = 0; for (int i = 1; i <= n; ++i) a[i] = read(), b[i].val = a[i], b[i].id = i; sort(b + 1, b + n + 1, cmp); for (int i = 1; i <= n; ++i) a[b[i].id] = i; for (int i = 1; i <= n; ++i) pos[a[i]] = i; for (int i = 1; i <= n - 2; ++i) { int p = pos[i]; while (p >= i + 2) { pos[a[p - 1]] = p, pos[a[p - 2]] = p - 1; pos[a[p]] = p - 2; swap(a[p - 2], a[p]); swap(a[p - 1], a[p]); ans[++m] = p - 2; p -= 2; } if (p == i + 1) { ans[++m] = i, ans[++m] = i; pos[a[p]] = p - 1; pos[a[p - 1]] = p + 1, pos[a[p + 1]] = p; int t1 = a[p - 1], t2 = a[p + 1]; a[p - 1] = a[p], a[p] = t2, a[p + 1] = t1; } } if (b[a[n - 1]].val > b[a[n]].val) { vis.clear(); bool flag = 0; for (int i = 1; i <= n; ++i) { if (!vis.count(b[i].val)) { vis[b[i].val] = b[i].id; a[b[i].id] = i; } else { a[b[i].id] = i; if (!flag) swap(a[vis[b[i].val]], a[b[i].id]); flag = 1; vis.erase(b[i].val); } } for (int i = 1; i <= n; ++i) pos[a[i]] = i; m = 0; for (int i = 1; i <= n - 2; ++i) { int p = pos[i]; while (p >= i + 2) { pos[a[p - 1]] = p, pos[a[p - 2]] = p - 1; pos[a[p]] = p - 2; swap(a[p - 2], a[p]); swap(a[p - 1], a[p]); ans[++m] = p - 2; p -= 2; } if (p == i + 1) { ans[++m] = i, ans[++m] = i; pos[a[p]] = p - 1; pos[a[p - 1]] = p + 1, pos[a[p + 1]] = p; int t1 = a[p - 1], t2 = a[p + 1]; a[p - 1] = a[p], a[p] = t2, a[p + 1] = t1; } } if (b[a[n - 1]].val > b[a[n]].val) { printf("-1\n"); } else { printf("%d\n", m); for (int i = 1; i <= m; ++i) printf("%d ", ans[i]); printf("\n"); } } else { printf("%d\n", m); for (int i = 1; i <= m; ++i) printf("%d ", ans[i]); printf("\n"); } } }
#include <bits/stdc++.h> using namespace std; void Print_a(vector<int>& a) { for (int& c : a) { cout << c << " "; } cout << endl; } int main() { int k; cin >> k; for (int l = 0; l < k; ++l) { int n; cin >> n; vector<int> a(n), b(n); vector<int> ans; int num_op = 0; for (int i = 0; i < n; ++i) { cin >> a[i]; } b = a; sort(b.begin(), b.end()); for (int i = 0; i <= n - 3; i++) { int j = i; while (a[j] != b[i]) { j++; } int temp; while (j != i) { if (j - i >= 2) { ans.push_back(j - 2 + 1); num_op += 1; temp = a[j - 2]; a[j - 2] = a[j]; a[j] = a[j - 1]; a[j - 1] = temp; j -= 2; } else if (j - i == 1) { ans.push_back(j - 1 + 1); ans.push_back(j - 1 + 1); num_op += 2; temp = a[j - 1]; a[j - 1] = a[j]; a[j] = a[j + 1]; a[j + 1] = temp; break; } } } int i_doub = -1; if (a[n - 2] > a[n - 1]) { int doub = b[n - 2]; for (int i = n - 3; i >= 0; --i) { if (doub == b[i]) { i_doub = i; break; } doub = b[i]; } if (i_doub == -1) { cout << -1 << endl; } else { int temp; for (int i = n - 3; i >= i_doub; --i) { ans.push_back(i + 1); num_op += 1; temp = a[i]; a[i] = a[i + 2]; a[i + 2] = a[i + 1]; a[i + 1] = temp; } } } else { i_doub = -2; } if (i_doub != -1) { cout << num_op << endl; for (int& c : ans) { cout << c << " "; } cout << endl; } } return 0; }
#include <bits/stdc++.h> using namespace std; int T, N; pair<int, int> arr[500]; int ct[501]; vector<int> mvs; vector<pair<int, int> > elems; void rot(int ind) { pair<int, int> tmp = arr[ind + 2]; arr[ind + 2] = arr[ind + 1]; arr[ind + 1] = arr[ind]; arr[ind] = tmp; } int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); cin >> T; while (T--) { cin >> N; memset(ct, 0, sizeof(int) * 501); elems.clear(); mvs.clear(); for (int i = (0); i < (N); i++) { cin >> arr[i].first; arr[i].second = ct[arr[i].first]++; elems.emplace_back(arr[i]); } sort(elems.begin(), elems.end()); long long inv = 0; bool dup = 0; for (int i = (0); i < (N); i++) { for (int j = (i + 1); j < (N); j++) { if (arr[j].first < arr[i].first) inv++; if (arr[j].first == arr[i].first) dup = 1; } } if (dup || !(inv & 1)) { if (inv & 1) { for (int i = (0); i < (N - 1); i++) if (elems[i].first == elems[i + 1].first) { elems[i].second++; elems[i + 1].second--; break; } } for (int i = (N - 1); i >= (0); i--) { int ind; for (int j = (0); j < (N); j++) if (arr[j] == elems[i]) { ind = j; break; } for (int j = (ind); j < (i); j++) { mvs.emplace_back(max(0, j - 1)); rot(max(0, j - 1)); } } cout << mvs.size() << '\n'; for (int mv : mvs) cout << mv + 1 << ' '; cout << '\n'; } else cout << "-1\n"; } }
#include <bits/stdc++.h> #pragma GCC optimize(2) #pragma GCC optimize(3) using namespace std; inline int read() { int x = 0, neg = 1; char op = getchar(); while (!isdigit(op)) { if (op == '-') neg = -1; op = getchar(); } while (isdigit(op)) { x = 10 * x + op - '0'; op = getchar(); } return neg * x; } inline void print(int x) { if (x < 0) { putchar('-'); x = -x; } if (x >= 10) print(x / 10); putchar(x % 10 + '0'); } const int N = 505; pair<int, int> a[N]; int p[N], n; void rotate(int x) { swap(p[x], p[x + 2]); swap(p[x + 1], p[x + 2]); } bool check() { for (register int i = 1; i < n; i++) { if (p[i] > p[i + 1]) { return 0; } } return 1; } void solve() { n = read(); for (register int i = 1; i <= n; i++) { int x = read(); a[i] = make_pair(x, i); } sort(a + 1, a + n + 1); for (register int i = 1; i <= n; i++) { p[a[i].second] = i; } int cnt = 0; for (register int i = 1; i <= n; i++) { for (register int j = i + 1; j <= n; j++) { if (p[i] > p[j]) { cnt++; } } } if (cnt & 1) { for (register int i = 1; i < n; i++) { if (a[i].first == a[i + 1].first) { swap(p[a[i].second], p[a[i + 1].second]); break; } } } vector<int> ans; for (register int i = 1; i <= n - 2; i++) { int pos = min_element(p + i, p + n + 1) - p; while (pos > i + 1) { rotate(pos - 2), ans.push_back(pos - 2); pos -= 2; } if (pos > i) { rotate(i), ans.push_back(i); rotate(i), ans.push_back(i); } } if (!check()) { puts("-1"); } else { printf("%d\n", (int)ans.size()); for (auto v : ans) { printf("%d ", v); } puts(""); } } int main() { int T = read(); while (T--) solve(); return 0; }
#include <bits/stdc++.h> using namespace std; int const inf = 1e8; int n; int a[1 << 10]; void shift(int pos) { int b[3]; b[0] = a[pos + 2]; b[1] = a[pos]; b[2] = a[pos + 1]; for (int j = 0; j < 3; ++j) a[pos + j] = b[j]; } void print(vector<int> &ans) { printf("%d\n", int(ans.size())); for (int i : ans) { printf("%d ", i); } printf("\n"); } void solve() { scanf("%d", &n); for (int i = 1; i <= n; ++i) { scanf("%d", a + i); } int inv = 0; vector<int> ans; for (int i = 1; i < n - 1; ++i) { int mn = a[i]; int pos = -1; for (int j = i + 1; j <= n; ++j) { if (a[j] < mn) { mn = a[j]; pos = j; } } if (pos == -1) continue; while (pos - i >= 2) { ans.push_back(pos - 2); shift(pos - 2); pos -= 2; } if (pos > i) { ans.push_back(i); ans.push_back(i); shift(i); shift(i); } } if (is_sorted(a + 1, a + 1 + n)) { print(ans); return; } if (a[n] == a[n - 2]) { shift(n - 2); ans.push_back(n - 2); return print(ans); } int pos = -1; for (int i = n - 2; i >= 1; --i) { if (a[i] == a[i - 1]) { pos = i - 1; break; } } if (pos == -1) { puts("-1"); return; } for (int i = n - 2; i >= pos; --i) { shift(i); ans.push_back(i); } assert(is_sorted(a + 1, a + 1 + n)); print(ans); } int main() { int T; for (scanf("%d", &T); T--;) { solve(); } }
#include <bits/stdc++.h> using namespace std; int n; int a[505]; int b[505]; int opt[250050]; int optnum; void triple_swap(int k) { swap(a[k + 1], a[k + 2]); swap(a[k], a[k + 1]); } void print() { for (int i = 0; i < n; i++) { printf("%d ", a[i]); } printf("\n"); } int main() { int T; scanf("%d", &T); while (T--) { scanf("%d", &n); for (int i = 0; i < n; i++) { scanf("%d", a + i); b[i] = a[i]; } sort(b, b + n); optnum = 0; for (int i = n; i >= 3; i--) { int maxIdx = 0; for (int j = 1; j < i; j++) if (a[j] >= a[maxIdx]) maxIdx = j; if (maxIdx == 0) { maxIdx = 1; opt[optnum++] = 0; triple_swap(0); } for (int j = maxIdx; j < i - 1; j++) { opt[optnum++] = j - 1; triple_swap(j - 1); } } bool flag = true; if (a[0] > a[1]) { flag = false; for (int i = 0; i < n - 2; i++) { opt[optnum++] = i; opt[optnum++] = i; triple_swap(i); triple_swap(i); if (a[i + 1] == a[i + 2]) break; } if (a[n - 2] <= a[n - 1]) flag = true; } if (!flag) printf("-1\n"); else { printf("%d\n", optnum); for (int i = 0; i < optnum; i++) { printf("%d ", opt[i] + 1); } printf("\n"); } } }
#include <bits/stdc++.h> using namespace std; int N; pair<int, int> elements[500]; vector<int> freq[501]; vector<int> ans; void swap(int i) { ans.emplace_back(i); pair<int, int> p1 = elements[i], p2 = elements[i + 1], p3 = elements[i + 2]; elements[i + 1] = p1; elements[i + 2] = p2; elements[i] = p3; } void solve(int size) { if (size <= 2) { return; } int max_ind = 0; for (int i = 1; i < size; ++i) { if (elements[max_ind] < elements[i]) { max_ind = i; } } for (int i = max_ind; i < size - 1; ++i) { swap(min(i, size - 3)); } solve(size - 1); } int main(void) { int T; scanf("%d", &T); while (T--) { ans.clear(); fill(freq, freq + 500, vector<int>()); scanf("%d", &N); for (int u, i = 0; i < N; ++i) { scanf("%d", &u); elements[i] = {u, freq[u].size()}; freq[u].emplace_back(i); } int num_inv = 0; for (int i = 0; i < N; ++i) { for (int j = i + 1; j < N; ++j) { num_inv += (elements[i] > elements[j]); } } bool poss = false; if (num_inv % 2 == 0) { poss = true; } else { for (int i = 1; i <= 500; ++i) { if (freq[i].size() > 1) { elements[freq[i][0]].second = 1; elements[freq[i][1]].second = 0; poss = true; break; } } } if (!poss) { printf("-1\n"); continue; } solve(N); printf("%d\n", (int)ans.size()); for (int i = 0; i < ans.size(); ++i) { printf("%d ", ++ans[i]); } printf("\n"); } return 0; }
#include <bits/stdc++.h> using namespace std; vector<int> v, ans; void op(int i) { swap(v[i], v[i + 1]); swap(v[i], v[i + 2]); if (ans.size() >= 2 && ans[ans.size() - 1] == i + 1 && ans[ans.size() - 2] == i + 1) ans.pop_back(), ans.pop_back(); else ans.push_back(i + 1); } void reach(int x, int y) { while (y > x + 1) op(y - 2), y -= 2; if (y == x + 1) op(y - 1), op(y - 1); } int main(int argc, char **argv) { ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); int t; cin >> t; while (t--) { int n, st = 0, temp = 0; ans.clear(); cin >> n; v.resize(n); vector<int> ar(501, -1); int val = -1, x, y; for (int i = 0; i < n; i++) { cin >> v[i]; if (ar[v[i]] != -1) val = v[i], x = ar[v[i]], y = i; ar[v[i]] = i; } if (val != -1) v[x] = v[y] = 2000; while (n - st > 3) { int mi = 1000, in; for (int j = st; j < n; j++) if (v[j] < mi) mi = v[j], in = j; reach(st, in); st++; } if (val == -1) { while (!(v[st] <= v[st + 1] && v[st + 1] <= v[st + 2])) { op(st), temp++; if (temp > 5) { cout << -1 << endl; goto brk; } } } else { while (v[st + 1] != 2000 || v[st + 2] != 2000) op(st); while (st >= 0 && val < v[st]) op(st), op(st), st--; } cout << ans.size() << endl; for (auto x : ans) cout << x << " "; cout << endl; brk:; } }
#include <bits/stdc++.h> using namespace std; int main() { ios::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL); int t; cin >> t; while (t--) { int n; cin >> n; vector<int> a(n), ans; for (int i = 0; i < n; i++) { cin >> a[i]; } auto cyc = [&](int idx) { swap(a[idx + 2], a[idx]); swap(a[idx + 1], a[idx + 2]); ans.push_back(idx); }; if (n == 3) { if (!is_sorted(a.begin(), a.end())) cyc(0); if (!is_sorted(a.begin(), a.end())) cyc(0); } for (int i = 0; i + 2 < n; i++) { vector<pair<int, int>> b(n); for (int j = 0; j < n; j++) { b[j] = {a[j], j}; } sort(b.begin(), b.end()); if (i < b[i].second) { for (int k = b[i].second - 2; k >= i; k -= 2) { cyc(k); } if ((b[i].second - i) & 1) { cyc(i); cyc(i); } } } if (a[n - 2] > a[n - 1]) { int x = -1; for (int i = 0; i + 2 < n; i++) { if (a[i] == a[i + 1]) { x = i; } } if (x != -1) { for (int i = x; i < n - 4; i++) { cyc(i); } cyc(n - 3); cyc(n - 4); for (int i = n - 5; i >= x; i--) { cyc(i); cyc(i); } } } if (a[n - 2] > a[n - 1]) cyc(n - 3); if (is_sorted(a.begin(), a.end()) && ans.size() <= n * n) { cout << ans.size() << '\n'; for (auto i : ans) cout << i + 1 << " "; cout << '\n'; } else { cout << -1 << '\n'; } } return 0; }
#include <bits/stdc++.h> using namespace std; const int MAXN = 500; pair<int, int> a[MAXN + 1]; int where[MAXN + 1]; vector<int> pos[MAXN + 1]; vector<int> ans; bool solve(int n) { vector<pair<int, int>> v(n + 1); for (int i = 1; i <= n; i++) { v[i] = a[i]; } int right = n; for (int i = MAXN; i >= 1; i--) { for (int j : pos[i]) { if (right <= 3) break; for (int k = where[j]; k <= right - 2; k++) { ans.push_back(k); swap(v[k + 1], v[k + 2]); swap(v[k], v[k + 1]); where[v[k].second] = k; where[v[k + 1].second] = k + 1; where[v[k + 2].second] = k + 2; } if (where[j] < right) { ans.push_back(right - 2); swap(v[right - 1], v[right]); swap(v[right - 2], v[right - 1]); where[v[right].second] = right; where[v[right - 1].second] = right - 1; where[v[right - 2].second] = right - 2; } right--; } } for (int i = 0; i < 4; i++) { if (v[1].first <= v[2].first && v[2].first <= v[3].first) break; ans.push_back(1); swap(v[2], v[3]); swap(v[1], v[2]); if (i == 3) return false; } return true; } int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); int t; cin >> t; while (t--) { int n; cin >> n; ans.clear(); for (int i = 1; i <= MAXN; i++) { pos[i].clear(); } for (int i = 1; i <= n; i++) { cin >> a[i].first; a[i].second = i; pos[a[i].first].push_back(i); where[i] = i; } if (solve(n)) { cout << (int)ans.size() << "\n"; for (int x : ans) cout << x << " "; cout << "\n"; } else { for (int i = 1; i <= n; i++) where[i] = i; ans.clear(); bool valid = false; for (int i = 1; i <= MAXN; i++) { if ((int)pos[i].size() > 1) { valid = true; int temp1 = pos[i].back(); pos[i].pop_back(); int temp2 = pos[i].back(); pos[i].pop_back(); pos[i].push_back(temp1); pos[i].push_back(temp2); break; } } if (valid) { solve(n); cout << (int)ans.size() << "\n"; for (int x : ans) cout << x << " "; cout << "\n"; } else { cout << "-1\n"; } } } return 0; }
#include <bits/stdc++.h> using namespace std; void solve() { long long n; cin >> n; long long a[n], b[n]; set<long long> s; for (long long i = 0; i < n; i++) { cin >> a[i]; s.insert(a[i]); b[i] = a[i]; } vector<long long> v; sort(b, b + n); for (long long i = 0; i < n; i++) { if (a[i] == b[i]) ; else { long long in, cnt = 1; for (long long j = i + 1; j < n; j++) { if (a[j] == b[i]) { in = j; break; } else { cnt++; } } if (in == n - 1 && i == n - 2) { if (s.size() == n) { cout << -1; return; } if (a[n - 1] == a[n - 3]) { v.push_back(n - 2); break; } for (long long j = n - 3; j >= 1; j -= 2) { v.push_back(j); v.push_back(j); v.push_back(j + 1); v.push_back(j + 1); if (a[j] == a[j - 1]) { break; } if (a[j - 1] == a[j - 2]) { v.push_back(j - 1); break; } } break; } while (cnt > 1) { swap(a[in], a[in - 2]); swap(a[in], a[in - 1]); in -= 2; cnt -= 2; v.push_back(in + 1); } if (cnt == 1) { swap(a[i], a[i + 1]); swap(a[i + 1], a[i + 2]); v.push_back(i + 1); v.push_back(i + 1); } } } cout << v.size() << endl; for (long long i = 0; i < v.size(); i++) cout << v[i] << " "; } int main() { ios::sync_with_stdio(false); cin.tie(0); cout.tie(0); long long tt = 1; cin >> tt; while (tt--) { solve(); cout << endl; } }
#include <bits/stdc++.h> using namespace std; int t, n, olda[505], a[505]; void rot(int ind) { swap(a[ind], a[ind + 1]); swap(a[ind], a[ind + 2]); } int main() { cin >> t; for (int amount = 0; amount < t; amount++) { cin >> n; vector<int> ans; vector<pair<int, int> > v; for (int i = 1; i <= n; i++) { cin >> olda[i]; a[i] = olda[i]; v.push_back({a[i], i}); } sort(v.begin(), v.end()); for (int i = 0; i < v.size(); i++) a[v[i].second] = i + 1; for (int i = 1; i <= n - 2; i++) { int ind = i; for (int j = i; j <= n; j++) { if (a[j] == i) { ind = j; break; } } while (ind != i) { if (ind - i >= 2) { ans.push_back(ind - 2); rot(ind - 2); ind -= 2; } else { ans.push_back(ind - 1); ans.push_back(ind - 1); rot(ind - 1); rot(ind - 1); ind--; } } } if (a[n] == n) { cout << ans.size() << '\n'; for (int i = 0; i < ans.size(); i++) cout << ans[i] << ' '; cout << '\n'; continue; } v.clear(); ans.clear(); for (int i = 1; i <= n; i++) { a[i] = olda[i]; v.push_back({a[i], i}); } sort(v.begin(), v.end()); for (int i = 0; i < v.size(); i++) a[v[i].second] = i + 1; for (int i = 1; i < v.size(); i++) { if (v[i].first == v[i - 1].first) { swap(a[v[i].second], a[v[i - 1].second]); break; } } for (int i = 1; i <= n - 2; i++) { int ind = i; for (int j = i; j <= n; j++) { if (a[j] == i) { ind = j; break; } } while (ind != i) { if (ind - i >= 2) { ans.push_back(ind - 2); rot(ind - 2); ind -= 2; } else { ans.push_back(ind - 1); ans.push_back(ind - 1); rot(ind - 1); rot(ind - 1); ind--; } } } if (a[n] == n) { cout << ans.size() << '\n'; for (int i = 0; i < ans.size(); i++) cout << ans[i] << ' '; cout << '\n'; } else cout << "-1\n"; } }
#include <bits/stdc++.h> using namespace std; vector<int> b; void rotate(int i) { swap(b[i], b[i + 1]); swap(b[i], b[i + 2]); } void solve() { int n; cin >> n; vector<int> a(n); for (int i = 0; i < n; i++) { cin >> a[i]; } vector<int> ans; bool flag = true; b = a; sort(a.begin(), a.end()); int sind = -1; for (int i = 0; i < n - 1; i++) { if (a[i] == a[i + 1]) sind = i; } for (int i = 0; i < n - 2; i++) { while (a[i] != b[i]) { int j; for (j = i + 1; j < n; j++) { if (b[j] == a[i]) break; } if (i + 2 >= j) { ans.emplace_back(i + 1); rotate(i); } else { ans.emplace_back(j - 1); rotate(j - 2); } } } for (int i = 0; i < n; i++) { if (a[i] != b[i]) flag = false; } if (!flag && sind != -1) { for (int i = n - 3; i >= sind; i--) { rotate(i); ans.emplace_back(i + 1); } } if (flag == false && sind == -1) { cout << -1 << '\n'; return; } else { cout << ans.size() << '\n'; for (int i = 0; i < int(ans.size()); i++) { cout << ans[i] << " "; } cout << '\n'; } } int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL); long long int t = 1; cin >> t; while (t--) { solve(); } }
#include <bits/stdc++.h> using namespace std; void solve() { int n; cin >> n; vector<int> v(n), temp, move; for (int i = 0; i < n; ++i) cin >> v[i]; temp = v; sort(temp.begin(), temp.end()); for (int i = 0; i < n - 2; ++i) { int ind; for (int j = i; j < n; ++j) { if (v[j] == temp[i]) { ind = j; break; } } if (ind == i) continue; ind -= 2; while (ind >= i) { int a = v[ind], b = v[ind + 1], c = v[ind + 2]; v[ind] = c; v[ind + 1] = a; v[ind + 2] = b; move.push_back(ind); ind -= 2; } ind += 2; if (ind != i) { --ind; int a = v[ind], b = v[ind + 1], c = v[ind + 2]; v[ind] = c; v[ind + 1] = a; v[ind + 2] = b; a = v[ind]; b = v[ind + 1]; c = v[ind + 2]; v[ind] = c; v[ind + 1] = a; v[ind + 2] = b; move.push_back(ind); move.push_back(ind); } } if (v[n - 2] > v[n - 1]) { if (v[n - 1] == v[n - 3]) move.push_back(n - 3); else { int ind = -1; for (int i = n - 4; i >= 0; --i) { if (v[i] == v[i + 1]) { ind = i; break; } } if (ind == -1) { cout << -1 << "\n"; return; } for (int i = ind; i <= n - 5; ++i) { move.push_back(i); } move.push_back(n - 3); move.push_back(n - 4); for (int i = n - 5; i >= ind; --i) { move.push_back(i); move.push_back(i); } } cout << move.size() << "\n"; for (auto i : move) cout << i + 1 << " "; cout << "\n"; } else { cout << move.size() << "\n"; for (auto i : move) cout << i + 1 << " "; cout << "\n"; } } int main() { ios::sync_with_stdio(0); cin.tie(0); cout.tie(0); int t; cin >> t; while (t--) solve(); }
#include <bits/stdc++.h> using namespace std; void change_stream(char* in, char* out) { ifstream fin; fin.open(in); ofstream fout; fout.open(out); if (fin && fout) { freopen(in, "r", stdin); freopen(out, "w", stdout); } } long long a[500], renum[500]; void shift(long long i) { long long p = a[i]; a[i] = a[i + 2]; a[i + 2] = a[i + 1]; a[i + 1] = p; renum[a[i]] = i; renum[a[i + 1]] = i + 1; renum[a[i + 2]] = i + 2; } void solve() { long long n; cin >> n; pair<long long, long long> s[n]; for (long long i = 0; i < n; i++) { cin >> a[i]; s[i] = {a[i], i}; } sort(s, s + n); for (long long i = 0; i < n; i++) { renum[i] = s[i].second; a[renum[i]] = i; } long long sdv = 0; for (long long i = 0; i < n; i++) for (long long j = i + 1; j < n; j++) if (a[i] > a[j]) sdv++; if (sdv % 2) { bool flag = false; for (long long i = 0; i < n - 1; i++) if (s[i].first == s[i + 1].first) { swap(a[s[i].second], a[s[i + 1].second]); renum[a[s[i].second]] = s[i].second; renum[a[s[i + 1].second]] = s[i + 1].second; flag = true; break; } if (!flag) { cout << "-1\n"; return; } } vector<long long> ans; for (long long i = n - 1; i > 1; i--) { while (renum[i] < i) { long long l = max(0ll, renum[i] - 1); ans.push_back(l); shift(l); } } cout << ans.size() << "\n"; for (long long i : ans) cout << i + 1 << ' '; cout << "\n"; } signed main() { change_stream("in", "out"); ios::sync_with_stdio(0); cin.tie(0); long long test_count = 1; cin >> test_count; while (test_count--) solve(); }
#include <bits/stdc++.h> using namespace std; int n; vector<int> arr, z; void rotate(int i) { z.push_back(i + 1); int x = arr[i + 2]; arr[i + 2] = arr[i + 1]; arr[i + 1] = arr[i]; arr[i] = x; } void solve() { cin >> n; arr.resize(n); for (auto &x : arr) cin >> x; z.clear(); for (int i = 0; i < n - 2; ++i) { int k = i; for (int j = i + 1; j < n; ++j) if (arr[j] < arr[k]) k = j; for (; k - 2 >= i; k -= 2) rotate(k - 2); if (k > i) { rotate(i); rotate(i); } } for (int i = n - 2; arr[i] > arr[i + 1]; rotate(--i)) if (i == 0) { cout << -1 << "\n"; return; } cout << z.size() << "\n"; for (auto x : z) cout << x << " "; cout << "\n"; } int main() { ios_base::sync_with_stdio(false); cin.tie(0); int t; cin >> t; while (t--) solve(); return 0; }
#include <bits/stdc++.h> using namespace std; const int MAX = 1e5 + 5; const int INF = 0x3f3f3f3f; int t, a[MAX], n; vector<int> list1; void solve() { scanf("%d", &t); while (t--) { list1.clear(); scanf("%d", &n); for (int i = 1; i <= n; ++i) { scanf("%d", &a[i]); } for (int i = 1; i < n; ++i) { for (int j = 1; j <= n - 2; ++j) { if (a[j] > a[j + 1]) { swap(a[j], a[j + 2]); swap(a[j], a[j + 1]); list1.push_back(j); list1.push_back(j); } else if (a[j + 1] > a[j + 2]) { swap(a[j], a[j + 1]); swap(a[j], a[j + 2]); list1.push_back(j); } } } bool flag = true; for (int i = 1; i < n; ++i) { if (a[i] > a[i + 1]) { flag = false; break; } } if (!flag) printf("-1\n"); else { int len = list1.size(); printf("%d\n", len); for (int i = 0; i < len; ++i) { printf("%d ", list1[i]); } printf("\n"); } } } int main(void) { solve(); return 0; }
#include <bits/stdc++.h> using namespace std; void solve() { int n; cin >> n; vector<int> a(n + 1); for (int i = 1; i <= n; ++i) { cin >> a[i]; } auto cycle = [&](int p) { int x = a[p + 2]; a[p + 2] = a[p + 1]; a[p + 1] = a[p]; a[p] = x; }; vector<int> ans; for (int st = 1; st + 2 < n; ++st) { int pos = st; for (int i = st + 1; i <= n; ++i) { if (a[i] < a[pos]) { pos = i; } } while (pos - 2 >= st) { ans.push_back(pos - 2); cycle(pos - 2); pos = pos - 2; } if (pos == st) { continue; } if (pos == st + 1) { ans.push_back(st); ans.push_back(st); cycle(st); cycle(st); continue; } } int delta = 0; while (delta < 3) { if (a[n - 2] <= a[n - 1] && a[n - 1] <= a[n]) { break; } ans.push_back(n - 2); cycle(n - 2); ++delta; } if (delta == 3) { if (n == 3) { cout << "-1\n"; return; } ans.pop_back(); ans.pop_back(); ans.pop_back(); while (true) { if (a[n - 2] <= a[n - 1] && a[n - 2] <= a[n]) { break; } ans.push_back(n - 2); cycle(n - 2); } int same = -1; for (int i = 1; i <= n - 3; ++i) { if (a[i] == a[i + 1]) { same = i; } } if (same == -1) { cout << "-1\n"; return; } int d = 0; while (same < n - 3) { ans.push_back(same); cycle(same); ++same; ++d; } ans.push_back(same); ans.push_back(same); cycle(same); cycle(same); ++same; ans.push_back(same); ans.push_back(same); cycle(same); cycle(same); while (d > 0) { ans.push_back(same - 2); ans.push_back(same - 2); cycle(same - 2); cycle(same - 2); --same; --d; } } cout << ans.size() << "\n"; for (auto i : ans) { cout << i << " "; } cout << "\n"; } int main() { ios::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL); int t = 1; cin >> t; while (t--) { solve(); } return 0; }
#include <bits/stdc++.h> using namespace std; template <typename Arg1> void __f(const char* name, Arg1&& arg1) { cout << name << " : " << arg1 << "\n"; } template <typename Arg1, typename... Args> void __f(const char* names, Arg1&& arg1, Args&&... args) { const char* comma = strchr(names + 1, ','); cout.write(names, comma - names) << " : " << arg1 << " | "; __f(comma + 1, args...); } inline long long sbt(long long x) { return __builtin_popcountll(x); } inline long long iceil(double a) { return (long long)(ceil(a)); } inline long long mul(long long a, long long b, long long m = (long long)(1e9 + 7)) { return ((a % m) * (b % m)) % m; } inline long long add(long long a, long long b, long long m = (long long)(1e9 + 7)) { return (a + b) % m; } inline long long sub(long long a, long long b, long long m = (long long)(1e9 + 7)) { return (a - b + m) % m; } long long fastpow(long long a, long long b, long long m = (long long)(1e9 + 7)) { long long res = 1; while (b > 0) { if (b & 1) res = mul(res, a, m); a = mul(a, a, m); b >>= 1; } return res; } long long modinv(long long a, long long m = (long long)(1e9 + 7)) { return fastpow(a, m - 2, m); } long long n; long long a[510], ranks[510]; vector<long long> v; long long count() { long long ct = 0; for (long i = 0; i < n; i++) { for (auto j = i + 1; j <= n - 1; j++) { if (ranks[i] > ranks[j]) { ct++; } } } return ct; } long long moves(long long i) { long long maxi = -1; for (auto j = i - 2; j <= i; j++) { maxi = max(maxi, ranks[j]); } long long c = 0, temp; while (ranks[i] != maxi) { v.push_back(i - 1); temp = ranks[i]; ranks[i] = ranks[i - 1]; ranks[i - 1] = ranks[i - 2]; ranks[i - 2] = temp; c++; } return c; } void get_ac() { v.clear(); cin >> n; set<long long> s; for (long i = 0; i < n; i++) { cin >> a[i]; s.insert(a[i]); } map<long long, vector<long long> > ind; for (long i = 0; i < n; i++) { ind[a[i]].push_back(i); } long long rank = 0; for (auto i : ind) { for (auto j : i.second) { ranks[j] = rank++; } } long long inv = count(); if (inv & 1) { bool f = 0; for (auto i : ind) { if ((long long)(i.second.size()) > 1) { swap(ranks[i.second[0]], ranks[i.second[1]]); f = 1; break; } } if (!f) { cout << -1; return; } } long long ans = 0; for (auto i = n - 1; i >= 2; i--) { for (auto j = 2; j <= i; j++) { long long c = moves(j); ans += c; } } if (ans <= n * n) { cout << ans; cout << "\n"; for (auto i : v) { cout << i << " "; } } else { cout << -1; } } int main() { cin.sync_with_stdio(false); cout.sync_with_stdio(false); cin.tie(NULL); long long testcases; cin >> testcases; while (testcases--) { get_ac(); cout << "\n"; } return 0; }
#include <bits/stdc++.h> using namespace std; void solve() { int n; cin >> n; vector<int> a(n); for (int i = (0); ((1) > 0 ? i < (n) : i > (n)); i += (1)) cin >> a[i]; vector<int> p(n); iota(p.begin(), p.end(), 0); sort(p.begin(), p.end(), [&](int i, int j) { return a[i] < a[j]; }); vector<int> vis(n); int cnt = n; for (int i = (0); ((1) > 0 ? i < (n) : i > (n)); i += (1)) { if (vis[i]) continue; for (int j = i; !vis[j]; j = p[j]) vis[j] = 1; cnt--; } if (cnt & 1) { bool ok = false; for (int i = (0); ((1) > 0 ? i < (n - 1) : i > (n - 1)); i += (1)) { if (a[p[i]] == a[p[i + 1]]) { ok = true; swap(p[i], p[i + 1]); break; } } if (!ok) { cout << -1 << '\n'; return; } } for (int i = (0); ((1) > 0 ? i < (n) : i > (n)); i += (1)) a[p[i]] = i; vector<int> t; auto shift = [&](int x) { t.push_back(x); swap(a[x], a[x + 2]); swap(a[x + 1], a[x + 2]); }; for (int i = (0); ((1) > 0 ? i < (n - 2) : i > (n - 2)); i += (1)) { int j = i; while (a[j] != i) j++; while (j != i) { if (j - 2 >= i) { shift(j - 2); j -= 2; } else { shift(j - 1); j++; } } } cout << (int)t.size() << '\n'; for (int i = (0); ((1) > 0 ? i < ((int)t.size()) : i > ((int)t.size())); i += (1)) cout << t[i] + 1 << " \n"[i == (int)t.size() - 1]; } int main() { ios::sync_with_stdio(0); cin.tie(0); int t; cin >> t; for (int i = (0); ((1) > 0 ? i < (t) : i > (t)); i += (1)) solve(); }
#include <bits/stdc++.h> using namespace std; mt19937 gen(time(0)); bool IS_ONE_TEST = 0; vector<int> res; int total = 0; bool proc(int idx, vector<int> &a) { if (!total) return 0; res.push_back(idx + 1); int temp = a[idx + 2]; a[idx + 2] = a[idx + 1]; a[idx + 1] = a[idx]; a[idx] = temp; --total; return 1; } void solve() { int n; cin >> n; res.clear(); vector<int> a(n); for (int i = 0; i < n; ++i) cin >> a[i]; vector<int> b = a; total = n * n; sort(a.begin(), a.end()); for (int z = 0; z < n; ++z) { for (int i = 0; i + 2 < n; ++i) { int mn = min({b[i], b[i + 1], b[i + 2]}); while (b[i] != mn && proc(i, b)) ; } for (int i = n - 1; i > 1; --i) { int mx = max({b[i], b[i - 1], b[i - 2]}); while (b[i] != mx && proc(i - 2, b)) ; } } if (a == b) { cout << res.size() << endl; for (auto &c : res) cout << c << " "; cout << endl; } else cout << -1 << endl; } int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL); cout << fixed << setprecision(15); int t; if (IS_ONE_TEST) t = 1; else cin >> t; while (t-- > 0) { solve(); } }
#include <bits/stdc++.h> inline char nc() { static char buf[1000000], *p1 = buf, *p2 = buf; return p1 == p2 && (p2 = (p1 = buf) + fread(buf, 1, 1000000, stdin), p1 == p2) ? EOF : *p1++; } inline void read(int &x) { static char c; for (c = getchar(); !('0' <= c && c <= '9'); c = getchar()) ; for (x = 0; ('0' <= c && c <= '9'); c = getchar()) x = x * 10 + c - 48; } void write(int x) { if (x < 10) { putchar('0' + x); return; } write(x / 10); putchar('0' + x % 10); } inline void writeln(int x) { if (x < 0) putchar('-'), x *= -1; write(x); putchar('\n'); } inline void writel(int x) { if (x < 0) putchar('-'), x *= -1; write(x); putchar(' '); } using namespace std; int T, a[1007], sb, ans[1007 * 1007], n, tot; void play(int x) { ans[++tot] = x; a[x] ^= a[x + 2], a[x + 2] ^= a[x], a[x] ^= a[x + 2]; a[x + 1] ^= a[x + 2], a[x + 2] ^= a[x + 1], a[x + 1] ^= a[x + 2]; } signed main() { read(T); while (T--) { read(n); tot = 0; for (int i = 1; i <= n; i++) read(a[i]); for (int i = 1; i <= n - 2; i++) { sb = i; for (int j = i + 1; j <= n; j++) if (a[j] < a[sb]) sb = j; while (sb >= i + 2) play(sb - 2), sb -= 2; if (sb == i + 1) { play(i), play(i); continue; } } for (int i = n; i >= 3; i--) { sb = i; for (int j = i - 1; j; j--) if (a[j] > a[sb]) sb = j; while (sb <= i - 2) play(sb), play(sb), sb += 2; if (sb == i - 1) { play(sb - 1); continue; } } for (int i = 1; i < n; i++) if (a[i] > a[i + 1]) tot = -1; writeln(tot); if (tot <= 0) continue; for (int i = 1; i < tot; i++) writel(ans[i]); writeln(ans[tot]); } return 0; }
#include <bits/stdc++.h> using namespace std; int ans[255000], a[510], tot; void move(int u) { int t1, t2, t3; t1 = a[u], t2 = a[u + 1], t3 = a[u + 2]; a[u] = t3, a[u + 1] = t1, a[u + 2] = t2; } int t, n, mn, mx, u; int main() { scanf("%d", &t); while (t--) { tot = 0; scanf("%d", &n); for (int i = 1; i <= n; i++) scanf("%d", &a[i]); for (int i = 1; i <= n - 2; i++) { mn = 1000; for (int j = i; j <= n; j++) if (a[j] < mn) mn = a[j], u = j; while (u >= i + 2) ans[++tot] = u - 2, move(u - 2), u -= 2; if (u == i + 1) move(i), move(i), ans[++tot] = i, ans[++tot] = i; } for (int i = n; i >= 3; i--) { mx = -1; for (int j = i; j >= 1; j--) if (a[j] > mx) mx = a[j], u = j; while (u <= i - 2) ans[++tot] = u, move(u), u += 2; if (u == i - 1) move(i - 2), ans[++tot] = i - 2; } for (int i = 1; i < n; i++) if (a[i] > a[i + 1]) tot = -1; if (tot == -1) printf("-1\n"); else { printf("%d\n", tot); for (int i = 1; i <= tot; i++) printf("%d ", ans[i]); printf("\n"); } } return 0; }
#include <bits/stdc++.h> inline char nc() { static char buf[1000000], *p1 = buf, *p2 = buf; return p1 == p2 && (p2 = (p1 = buf) + fread(buf, 1, 1000000, stdin), p1 == p2) ? EOF : *p1++; } inline void read(int &x) { static char c; for (c = getchar(); !('0' <= c && c <= '9'); c = getchar()) ; for (x = 0; ('0' <= c && c <= '9'); c = getchar()) x = x * 10 + c - 48; } void write(int x) { if (x < 10) { putchar('0' + x); return; } write(x / 10); putchar('0' + x % 10); } inline void writeln(int x) { if (x < 0) putchar('-'), x *= -1; write(x); putchar('\n'); } inline void writel(int x) { if (x < 0) putchar('-'), x *= -1; write(x); putchar(' '); } using namespace std; int T, a[1007], sb, ans[1007 * 1007], n, tot; void play(int x) { ans[++tot] = x; a[x] ^= a[x + 2], a[x + 2] ^= a[x], a[x] ^= a[x + 2]; a[x + 1] ^= a[x + 2], a[x + 2] ^= a[x + 1], a[x + 1] ^= a[x + 2]; } signed main() { read(T); while (T--) { read(n); tot = 0; for (int i = 1; i <= n; i++) read(a[i]); for (int i = 1; i <= n - 2; i++) { sb = i; for (int j = i + 1; j <= n; j++) if (a[j] < a[sb]) sb = j; while (sb >= i + 2) play(sb - 2), sb -= 2; if (sb == i + 1) { play(i), play(i); } } for (int i = n; i >= 3; i--) { sb = i; for (int j = i - 1; j; j--) if (a[j] > a[sb]) sb = j; while (sb <= i - 2) play(sb), play(sb), sb += 2; if (sb == i - 1) { play(sb - 1); } } for (int i = 1; i < n; i++) if (a[i] > a[i + 1]) tot = -1; writeln(tot); if (tot <= 0) continue; for (int i = 1; i < tot; i++) writel(ans[i]); writeln(ans[tot]); } return 0; }
#include <bits/stdc++.h> using namespace std; int main() { long long t; cin >> t; while (t--) { long long n, n1, flag2 = 0; cin >> n; n1 = n; vector<long long> vect(n + 1), ans; set<pair<long long, long long>, greater<pair<long long, long long> > > set1; map<long long, long long> map1; for (int i = 1; i <= n; i++) { cin >> vect[i]; map1[vect[i]] += 1; if (map1[vect[i]] > 1) flag2 = vect[i]; set1.insert({vect[i], i}); } while (n1 >= 3) { pair<long long, long long> p = *set1.begin(); set1.erase(p); int i; for (i = p.second; i <= n1 - 2; i += 2) { ans.push_back(i); ans.push_back(i); set1.erase({vect[i + 1], i + 1}); set1.erase({vect[i + 2], i + 2}); set1.insert({vect[i + 1], i}); set1.insert({vect[i + 2], i + 1}); swap(vect[i + 1], vect[i]); swap(vect[i + 2], vect[i + 1]); } if (i == n1 - 1) { ans.push_back(i - 1); set1.erase({vect[i - 1], i - 1}); set1.erase({vect[i + 1], i + 1}); set1.insert({vect[i + 1], i - 1}); set1.insert({vect[i - 1], i}); swap(vect[i], vect[i + 1]); swap(vect[i], vect[i - 1]); } n1--; } long long val = flag2; for (int i = 3; i <= n; i++) { if (vect[i] == flag2) { flag2 = i; break; } } if (flag2 != 0 || vect[1] <= vect[2]) { if (vect[3] == vect[1]) { ans.push_back(1); ans.push_back(1); } else if (vect[1] > vect[2]) { for (int i = 1; i <= flag2 - 3; i++) { ans.push_back(i); } ans.push_back(flag2 - 2); ans.push_back(flag2 - 2); { ans.push_back(flag2 - 1); ans.push_back(flag2 - 1); } for (int i = flag2 - 3; i >= 1; i--) { ans.push_back(i); ans.push_back(i); } } cout << ans.size() << "\n"; for (int i = 0; i < ans.size(); i++) cout << ans[i] << " "; cout << "\n"; } else cout << "-1\n"; } return 0; }
#include <bits/stdc++.h> using namespace std; const int inf = 1 << 30; const long long mod = 1e9 + 7; const long long linf = 1LL << 62; const double EPS = 1e-7; template <class T> void chmin(T& x, T y) { if (x > y) x = y; } template <class T> void chmax(T& x, T y) { if (x < y) x = y; } void culc(int& a, int& b, int& c) { swap(b, c); swap(a, b); } void solve() { int n; cin >> n; vector<int> a(n); for (int i = 0; i < n; i++) cin >> a[i]; vector<int> ans; for (int i = 0; i < n - 2; i++) { auto it = min_element(a.begin() + i, a.end()) - a.begin(); if (i % 2 != it % 2) { if (it < n - 1) culc(a[it - 1], a[it], a[it + 1]), ans.push_back(it - 1), it++; else { culc(a[it - 2], a[it - 1], a[it]); culc(a[it - 2], a[it - 1], a[it]); ans.push_back(it - 2); ans.push_back(it - 2); it--; } } while (it != i) { culc(a[it - 2], a[it - 1], a[it]); ans.push_back(it - 2); it -= 2; } } bool flag = true; if (a[n - 1] < a[n - 2]) { flag = false; for (int i = n - 3; i >= 0; i--) { culc(a[i], a[i + 1], a[i + 2]); ans.push_back(i); if (a[i] <= a[i + 1]) { flag = true; break; } } } if (!flag) { cout << -1 << endl; return; } cout << ans.size() << endl; for (auto u : ans) cout << u + 1 << " "; cout << endl; } int main() { int t; cin >> t; while (t--) { solve(); } }
#include <bits/stdc++.h> using namespace std; string ys = "Yes\n", no = "No\n"; string imp = "IMPOSSIBLE\n"; long long mod = 1e9 + 7, inf = 1e9; long long maxn = 501; vector<long long> a(maxn); void d(long long ind) { swap(a[ind + 1], a[ind + 2]); swap(a[ind], a[ind + 1]); return; } void print(long long t) { for (long long i = 0; i < t; i++) { cout << a[i] << " "; } cout << '\n'; return; } int32_t main() { ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0); long long t = 1; cin >> t; for (; t; t--) { long long n; cin >> n; vector<long long> b(n); for (long long i = 0; i < n; i++) { cin >> a[i]; b[i] = a[i]; } sort(b.begin(), b.end()); if (n == 3) { if (a[0] == b[0] && a[1] == b[1] && a[2] == b[2]) { cout << 0 << '\n' << '\n'; continue; } if (a[2] == b[0] && a[0] == b[1] && a[1] == b[2]) { cout << 1 << '\n' << 1 << '\n'; continue; } if (a[1] == b[0] && a[2] == b[1] && a[0] == b[2]) { cout << 2 << '\n' << 1 << " " << 1 << '\n'; continue; } cout << -1 << '\n'; continue; } vector<long long> ans; bool ok = true; for (long long i = 0; i < n && ok; i++) { if (a[i] == b[i]) continue; long long j = i + 1; for (; j < n; j++) if (a[j] == b[i]) break; if (j == i + 1 && j != n - 1) { ans.push_back(j); ans.push_back(j); d(i); d(i); continue; } if (j == i + 1 && j == n - 1) { bool fl = true; long long k = i - 1; for (; k >= 0; k--) { if (b[k] == b[k + 1]) { break; } } if (k == -1) { ok = false; cout << -1 << '\n'; break; } while (i != k) { ans.push_back(i); i--; } swap(a[n - 2], a[n - 1]); continue; } if ((j - i) % 2 == 1) { if (j != n - 1) { ans.push_back(j); ans.push_back(j); d(j - 1); d(j - 1); j--; } else { ans.push_back(j - 1); ans.push_back(j - 2); d(j - 2); j -= 2; d(j - 1); j++; } } while (j != i) { ans.push_back(j - 1); d(j - 2); j -= 2; } } if (ok) { cout << ans.size() << '\n'; for (auto el : ans) { cout << el << " "; } cout << '\n'; } } return 0; }
#include <bits/stdc++.h> using namespace std; int a[505]; int sorted_a[505]; void rot(int i) { i--; int temp = a[i + 2]; a[i + 2] = a[i + 1]; a[i + 1] = a[i]; a[i] = temp; } int main() { ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0); int cases; cin >> cases; while (cases--) { int n; cin >> n; for (int i = 0; i < n; i++) { cin >> a[i]; sorted_a[i] = a[i]; } sort(sorted_a, sorted_a + n); vector<int> ans; for (int i = n - 1; i > 1; i--) { int j = i; while (a[j] != sorted_a[i]) j--; if (j == 0) { ans.push_back(1); rot(1); j++; } for (; j < i; j++) { ans.push_back(j); rot(j); } } if (a[0] != sorted_a[0]) { if (a[0] == a[2]) { ans.push_back(1); ans.push_back(1); rot(1); rot(1); } else { for (int i = 2; i < n - 1; i++) { if (a[i] == a[i + 1]) { for (int j = i; j >= 1; j--) { ans.push_back(j); rot(j); } break; } } } } if (a[0] == sorted_a[0]) { cout << ans.size() << "\n"; for (int i : ans) cout << i << " "; cout << "\n"; } else cout << "-1\n"; } return 0; }
#include <bits/stdc++.h> const int N = 502; void sw(float* x) { float tmp = *x; *x = *(x + 2); *(x + 2) = *(x + 1); *(x + 1) = tmp; } int main() { int _t; scanf("%d", &_t); while (_t--) { static float arr[N]; static int anss[N * N]; static int tm[N]; memset(tm, 0, sizeof(tm)); int n; scanf("%d", &n); int f2 = -1; for (int i = 1; i <= n; i++) { int a; scanf("%d", &a); tm[a]++; if (tm[a] == 2) f2 = a; arr[i] = a + 0.0001 * tm[a]; } int nx = 0; for (int i = 1; i < n; i++) for (int j = i + 1; j <= n; j++) if (arr[i] > arr[j]) nx++; if (nx & 1) { if (f2 != -1) { int f21, f22; for (int i = 1; i <= n; i++) if (((int)arr[i]) == f2) { f21 = i; break; } for (int i = n; i >= 1; i--) if (((int)arr[i]) == f2) { f22 = i; break; } std::swap(arr[f21], arr[f22]); } else { printf("-1\n"); continue; } } nx = 0; for (int i = 1; i < n; i++) for (int j = i + 1; j <= n; j++) if (arr[i] > arr[j]) nx++; int ans = 0; while (nx) { for (int i = 1; i <= n - 2; i++) { if (arr[i] < arr[i + 2] && arr[i + 2] < arr[i + 1] || arr[i] > arr[i + 2] && arr[i + 2] > arr[i + 1]) { sw(arr + i); anss[++ans] = i; } if (arr[i] < arr[i + 1] && arr[i] > arr[i + 2] || arr[i] > arr[i + 1] && arr[i + 1] > arr[i + 2]) { sw(arr + i); nx -= 2; anss[++ans] = i; } } } printf("%d\n", ans); for (int i = 1; i <= ans; i++) printf("%d ", anss[i]); printf("\n"); } return 0; }
#include <bits/stdc++.h> const int N = 502; void sw(float *x) { float tmp = *x; *x = *(x + 2); *(x + 2) = *(x + 1); *(x + 1) = tmp; } int nxs(float *p, int n) { int res = 0; for (int i = 0; i < n - 1; i++) for (int j = i + 1; j < n; j++) if (p[i] > p[j]) res++; return res; } int diff(float *p) { static float tmp[3]; for (int i = 0; i < 3; i++) tmp[i] = p[i]; sw(tmp); return nxs(tmp, 3) - nxs(p, 3); } int main() { int _t; scanf("%d", &_t); while (_t--) { static float arr[N]; static int anss[N * N]; static int tm[N]; memset(tm, 0, sizeof(tm)); int n; scanf("%d", &n); int f2 = -1; for (int i = 1; i <= n; i++) { int a; scanf("%d", &a); tm[a]++; if (tm[a] == 2) f2 = a; arr[i] = a + 0.0001 * tm[a]; } int nx = 0; for (int i = 1; i < n; i++) for (int j = i + 1; j <= n; j++) if (arr[i] > arr[j]) nx++; if (nx & 1) { if (f2 != -1) { int f21 = -1, f22 = -1; for (int i = 1; i <= n; i++) if (((int)arr[i]) == f2) { if (f21 == -1) f21 = i; else if (f22 == -1) f22 = i; else break; } std::swap(arr[f21], arr[f22]); nx++; } else { printf("-1\n"); continue; } } int ans = 0; while (nx) for (int i = 1; i <= n - 2; i++) for (int df = diff(arr + i); df <= 0; sw(arr + i), df = diff(arr + i), anss[++ans] = i) nx += df; printf("%d\n", ans); for (int i = 1; i <= ans; i++) printf("%d ", anss[i]); printf("\n"); } return 0; }
#include <bits/stdc++.h> const double eps = 1e-9; const long double pi = acos(-1.0); using namespace std; void solve() { int n; cin >> n; vector<int> a(n); vector<pair<int, int>> b(n); for (int i = 0; i < n; i++) { cin >> a[i]; b[i] = {a[i], i}; } sort(b.begin(), b.end()); for (int i = 0; i < n; i++) { a[b[i].second] = i; } int kol = 0; for (int i = 0; i < n - 1; i++) { for (int j = i + 1; j < n; j++) { if (j > i && a[j] < a[i]) kol++; } } if (kol & 1) { for (int i = 0; i < n - 1; i++) if (b[i].first == b[i + 1].first) { swap(a[b[i].second], a[b[i + 1].second]); kol ^= 1; break; } } if (kol & 1) { cout << -1 << endl; return; } vector<int> ans; for (int i = 0; i < n - 3; i++) { int mn = n + 1; int ind = -1; for (int j = i; j < n; j++) if (a[j] < mn) mn = a[j], ind = j; while (1) { if (ind - 2 >= i) { int tmp = a[ind]; a[ind] = a[ind - 1]; a[ind - 1] = a[ind - 2]; a[ind - 2] = tmp; ind -= 2; ans.push_back(ind + 1); } else break; } if (ind != i) { ans.push_back(i + 1); ans.push_back(i + 1); int tmp = a[i]; a[i] = a[i + 1]; a[i + 1] = a[i + 2]; a[i + 2] = tmp; } } if (a[n - 2] > a[n - 1] && a[n - 2] > a[n - 3] && a[n - 3] > a[n - 1]) { ans.push_back(n - 3 + 1); } else if (a[n - 3] > a[n - 2] && a[n - 3] > a[n - 1] && a[n - 1] > a[n - 2]) { ans.push_back(n - 3 + 1); ans.push_back(n - 3 + 1); } cout << ans.size() << endl; for (int x : ans) cout << x << " "; cout << endl; } int main() { ios::sync_with_stdio(NULL), cin.tie(0), cout.tie(0); cout.setf(ios::fixed), cout.precision(10); int step; step = 1; cin >> step; for (int i = 1; i <= step; i++) { solve(); } }
#include <bits/stdc++.h> using namespace std; const int MAXN = 505; int arr[MAXN]; int arr_copy[MAXN]; void rotate(int ind) { int num1 = arr[ind], num2 = arr[ind + 1], num3 = arr[ind + 2]; arr[ind] = num3; arr[ind + 1] = num1; arr[ind + 2] = num2; } void swap_back(int ind, int distance, vector<int>& actions) { if (distance == 0) return; if (distance == 1) { actions.push_back(ind - 1); actions.push_back(ind - 1); rotate(ind - 1); rotate(ind - 1); return; } actions.push_back(ind - 2); rotate(ind - 2); swap_back(ind - 2, distance - 2, actions); } void swap_back2(int ind, int distance, vector<int>& actions) { if (distance <= 1) return; actions.push_back(ind - 2); rotate(ind - 2); swap_back2(ind - 2, distance - 2, actions); } int main() { ios_base::sync_with_stdio(0); int t; cin >> t; for (int test = 1; test <= t; test++) { int n; cin >> n; for (int i = 1; i <= n; i++) { cin >> arr[i]; arr_copy[i] = arr[i]; } vector<int> actions; for (int i = 1; i <= n - 2; i++) { int min_ind = -1, min_val = 1e9; for (int j = i; j <= n; j++) { if (arr[j] < min_val) min_val = arr[j], min_ind = j; } swap_back(min_ind, min_ind - i, actions); } if (arr[n - 1] <= arr[n]) { cout << actions.size() << '\n'; for (int i : actions) cout << i << ' '; cout << '\n'; continue; } for (int i = 1; i <= n; i++) arr[i] = arr_copy[i] * 501; int done = 0; for (int i = 1; i <= n; i++) { int num = arr[i] + 1; for (int j = i + 1; j <= n; j++) { if (arr[i] == arr[j]) { arr[j] = num; num++; } } } actions.clear(); for (int i = 1; i <= n - 2; i++) { int min_ind = -1, min_val = 1e9; for (int j = i; j <= n; j++) { if (arr[j] < min_val) min_val = arr[j], min_ind = j; } swap_back(min_ind, min_ind - i, actions); } if (arr[n - 1] / 501 <= arr[n] / 501) { cout << actions.size() << '\n'; for (int i : actions) cout << i << ' '; cout << '\n'; continue; } for (int i = 1; i <= n; i++) arr[i] = arr_copy[i] * 501; done = 0; for (int i = 1; i <= n; i++) { int num = arr[i] + 1; for (int j = i + 1; j <= n; j++) { if (arr[i] == arr[j]) { arr[j] = num; num++; } } } for (int i = 1; i <= n; i++) { for (int j = i + 1; j <= n; j++) { if (arr[j] == arr[i] + 1) { swap(arr[i], arr[j]); done = 1; break; } } if (done) break; } actions.clear(); for (int i = 1; i <= n - 2; i++) { int min_ind = -1, min_val = 1e9; for (int j = i; j <= n; j++) { if (arr[j] < min_val) min_val = arr[j], min_ind = j; } swap_back(min_ind, min_ind - i, actions); } if (arr[n - 1] / 501 <= arr[n] / 501) { cout << actions.size() << '\n'; for (int i : actions) cout << i << ' '; cout << '\n'; continue; } else cout << -1 << '\n'; } return 0; }
#include <bits/stdc++.h> const int N = 502; void sw(float *x) { float tmp = *x; *x = *(x + 2); *(x + 2) = *(x + 1); *(x + 1) = tmp; } int nxs(float *p, int n) { int res = 0; for (int i = 0; i < n - 1; i++) for (int j = i + 1; j < n; j++) if (p[i] > p[j]) res++; return res; } int diff(float *p) { static float tmp[3]; for (int i = 0; i < 3; i++) tmp[i] = p[i]; sw(tmp); return nxs(tmp, 3) - nxs(p, 3); } int main() { int _t; scanf("%d", &_t); while (_t--) { static float arr[N]; static int anss[N * N]; static int tm[N]; memset(tm, 0, sizeof(tm)); int n; scanf("%d", &n); int f2 = -1; for (int i = 1; i <= n; i++) { int a; scanf("%d", &a); tm[a]++; if (tm[a] == 2) f2 = a; arr[i] = a + 0.0001 * tm[a]; } int nx = nxs(arr + 1, n); if (nx & 1) { if (f2 != -1) { int f21 = -1, f22 = -1; for (int i = 1; i <= n; i++) if (((int)arr[i]) == f2) { if (f21 == -1) f21 = i; else if (f22 == -1) f22 = i; else break; } std::swap(arr[f21], arr[f22]); nx++; } else { printf("-1\n"); continue; } } int ans = 0; while (nx) for (int i = 1; i <= n - 2; i++) for (int df = diff(arr + i); df <= 0; sw(arr + i), df = diff(arr + i), anss[++ans] = i) nx += df; printf("%d\n", ans); for (int i = 1; i <= ans; i++) printf("%d ", anss[i]); printf("\n"); } return 0; }
#include <bits/stdc++.h> using namespace std; void solve() { long long n; cin >> n; ; string str; cin >> str; ; map<long long, long long> mp; mp[0] = 1; long long sum = 0; long long ans = 0; for (long long i = 0; i < str.size(); i++) { sum += (str[i] - '0') - 1; ans += mp[sum]; mp[sum]++; } cout << ans << "\n"; } int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); long long t = 1; cin >> t; while (t--) { solve(); } return 0; }
#include <bits/stdc++.h> using namespace std; long long func(long long x) { return (x * (x - 1)) / 2; } int32_t main() { ios_base ::sync_with_stdio(0); cin.tie(0); cout.tie(0); long long t; cin >> t; while (t--) { long long n; cin >> n; string s; cin >> s; long long a[n]; for (long long i = 0; i < n; i++) a[i] = (long long)(s[i] - '0'); long long prefix[n]; prefix[0] = a[0]; for (long long i = 1; i < n; i++) prefix[i] = prefix[i - 1] + a[i]; long long aux[n]; for (long long i = 0; i < n; i++) aux[i] = (i + 1) - prefix[i]; map<long long, long long> freq; for (long long i = 0; i < n; i++) freq[aux[i]]++; long long res = 0; for (auto s : freq) res += func(s.second); for (long long i = 0; i < n; i++) { if (prefix[i] == i + 1) res++; } cout << res << "\n"; } return 0; }
#include <bits/stdc++.h> using namespace std; int main() { int tt; cin >> tt; while (tt--) { int n; cin >> n; vector<int> arr(n), pr(n + 1); pr[0] = 0; for (int i = 0; i < n; i++) { char c; cin >> c; arr[i] = c - '0'; pr[i + 1] = pr[i] + arr[i]; } vector<int> i_minus_pr(n + 1); map<int, long long> mp; long long ans = 0; for (int i = 0; i < n + 1; i++) { ans += mp[i - pr[i]]++; } cout << ans << endl; } return 0; }
#include <bits/stdc++.h> using namespace std; void solve(); int32_t main() { ios::sync_with_stdio(0); cin.tie(0); cout.tie(0); ; long long _ = 1; cin >> _; while (_--) solve(); return 0; } void solve() { long long n; cin >> n; string s; cin >> s; long long sum = 0, res = 0; map<long long, long long> mp; mp[0] = 1; for (long long i = 1; i <= n; i++) { sum += s[i - 1] - '0'; res += mp[sum - i]; mp[sum - i]++; } cout << res << "\n"; }
#include <bits/stdc++.h> using namespace std; void solve() { int n; cin >> n; string s; cin >> s; vector<long long> sum(n); sum[0] = s[0] - '0'; map<long long, long long> m; m[1] = 1; long long ans = 0; for (int i = 0; i < n; i++) { if (i > 0) sum[i] = sum[i - 1] + s[i] - '0'; ans += m[sum[i] - i]; m[sum[i] - i]++; } cout << ans << endl; return; } int main() { long long t; cin >> t; while (t--) { solve(); } return 0; }
#include <bits/stdc++.h> using namespace std; int main() { ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0); ; long long t; cin >> t; while (t--) { long long n, ans = 0, p = 0; map<long long, long long> mp; mp[0] = 1; string s; cin >> n; cin >> s; for (long long i = 0; i < (long long)(s).size(); i++) { if (s[i] == '0') p--; else p += (long long)(s[i] - '0') - 1; ans += (long long)mp[p]; mp[p]++; } cout << ans << '\n'; } }
#include <bits/stdc++.h> #pragma GCC optimize("O3") #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx") #pragma GCC optimize("unroll-loops") using namespace std; struct fhash { static uint64_t splitmix64(uint64_t x) { x += 0x9e3779b97f4a7c15; x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9; x = (x ^ (x >> 27)) * 0x94d049bb133111eb; return x ^ (x >> 31); } size_t operator()(uint64_t x) const { static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count(); return splitmix64(x + FIXED_RANDOM); } }; mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count()); long long randint(long long a, long long b) { return uniform_int_distribution<long long>(a, b)(rng); } template <class T> int fd(const T& n) { return (int)(n / pow(10, (int)log10(n))); } long long fstTrue(function<bool(long long)> f, long long lower_bound, long long rb) { while (lower_bound < rb) { long long mb = (lower_bound + rb) / 2; f(mb) ? rb = mb : lower_bound = mb + 1; } return lower_bound; } long long lstTrue(function<bool(long long)> f, long long lower_bound, long long rb) { while (lower_bound < rb) { long long mb = (lower_bound + rb + 1) / 2; f(mb) ? lower_bound = mb : rb = mb - 1; } return lower_bound; } bool pow2(int i) { return i && (i & -i) == i; } constexpr int pct(int x) { return __builtin_popcount(x); } constexpr int bits(int x) { return 31 - __builtin_clz(x); } long long gcd(long long a, long long b) { return b ? gcd(b, a % b) : a; } long long cdiv(long long a, long long b) { return a / b + ((a ^ b) > 0 && a % b); } template <class T> bool chmin(T& a, const T& b) { return b < a ? a = b, 1 : 0; } template <class T> bool chmax(T& a, const T& b) { return a < b ? a = b, 1 : 0; } template <class T> void remdup(vector<T>& v) { sort((v).begin(), (v).end()); v.erase(unique((v).begin(), (v).end()), end(v)); } template <class A, class B, class C> string to_string(tuple<A, B, C> p); template <class A, class B, class C, class D> string to_string(tuple<A, B, C, D> p); string to_string(char c) { return string(1, c); } string to_string(bool b) { return to_string((int)b); } string to_string(const char* s) { return (string)s; } string to_string(string s) { return s; } template <class A> string to_string(complex<A> c) { stringstream ss; ss << c; return ss.str(); } string to_string(vector<bool> v) { string res = "{"; for (int i = (0); i < (((int)(v).size())); ++i) res += char('0' + v[i]); res += "}"; return res; } template <size_t SZ> string to_string(bitset<SZ> b) { string res = ""; for (int i = (0); i < (((int)(b).size())); ++i) res += char('0' + b[i]); return res; } template <class A, class B> string to_string(pair<A, B> p); template <class T> string to_string(T v) { bool fst = 1; string res = ""; for (const auto& x : v) { if (!fst) res += " "; fst = 0; res += to_string(x); } return res; } template <class A, class B> string to_string(pair<A, B> p) { return to_string(p.first) + " " + to_string(p.second); } template <class A, class B, class C> string to_string(tuple<A, B, C> p) { return to_string(get<0>(p)) + " " + to_string(get<1>(p)) + " " + to_string(get<2>(p)); } template <class A, class B, class C, class D> string to_string(tuple<A, B, C, D> p) { return to_string(get<0>(p)) + " " + to_string(get<1>(p)) + " " + to_string(get<2>(p)) + " " + to_string(get<3>(p)); } template <class A> void re(complex<A>& c); template <class A, class B> void re(pair<A, B>& p); template <class A> void re(vector<A>& v); template <class A, size_t SZ> void re(array<A, SZ>& a); template <class T> void re(T& x) { cin >> x; } void re(double& d) { string t; re(t); d = stod(t); } void re(long double& d) { string t; re(t); d = stold(t); } template <class H, class... T> void re(H& h, T&... t) { re(h); re(t...); } template <class A> void re(complex<A>& c) { A a, b; re(a, b); c = {a, b}; } template <class A, class B> void re(pair<A, B>& p) { re(p.first, p.second); } template <class A> void re(vector<A>& x) { for (auto& a : x) re(a); } template <class A, size_t SZ> void re(array<A, SZ>& x) { for (auto& a : x) re(a); } template <class A> void pr(A x) { cout << to_string(x); } template <class H, class... T> void pr(const H& h, const T&... t) { pr(h); pr(t...); } void ps() { pr("\n"); } template <class H, class... T> void ps(const H& h, const T&... t) { pr(h); if (sizeof...(t)) pr(" "); ps(t...); } void DBG() { cerr << "]" << endl; } template <class H, class... T> void DBG(H h, T... t) { cerr << to_string(h); if (sizeof...(t)) cerr << ", "; DBG(t...); } const int di[4] = {-1, 0, 1, 0}, dj[4] = {0, 1, 0, -1}; const int di8[8] = {-1, -1, 0, 1, 1, 1, 0, -1}, dj8[8] = {0, 1, 1, 1, 0, -1, -1, -1}; void IOS(int n) { ios::sync_with_stdio(0); cin.tie(0); cout.tie(0); cout.precision(n); cerr.precision(n); cerr << fixed; cout << fixed; } void solve() { int n; string a; re(n, a); long long ans = 0, s = 0; map<int, int> m; m[0]++; for (int i = (0); i < (n); ++i) { s += a[i] - '0'; ans += m[s - (i + 1)]; m[s - (i + 1)]++; } ps(ans); } int main() { IOS(10); int t = 1; re(t); for (int i = (0); i < (t); ++i) solve(); }
#include <bits/stdc++.h> using namespace std; int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL); ; long long t; cin >> t; while (t--) { long long n, i, j, a, count1 = 0, sum = 0; cin >> n; string s, temp; cin >> s; long long arr[n]; for (i = 0; i < n; i++) { temp = s[i]; arr[i] = stoi(temp); } for (i = 0; i < n; i++) { arr[i] = arr[i] - 1; } map<long long, long long> mm; sum = 0; mm[0] = 1; count1 = 0; for (i = 0; i < n; i++) { sum = sum + arr[i]; count1 = count1 + mm[sum]; mm[sum]++; } cout << count1 << "\n"; } }
#include <bits/stdc++.h> using namespace std; #pragma GCC target("avx2") #pragma GCC optimization("O3") #pragma GCC optimization("unroll-loops") #pragma comment(linker, "/stack:200000000") #pragma GCC optimize("Ofast") #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native") const int N = 100005; int n, ara[N]; int main() { int t; cin >> t; while (t--) { cin >> n; string str; cin >> str; for (int i = 1; i <= n; i++) { char ch = str[i - 1]; int d = ch - '0'; ara[i] = d - 1; } map<int, int> mp; mp[0] = 1; int s = 0; long long ans = 0; for (int i = 1; i <= n; i++) { s += ara[i]; ans += mp[s]; mp[s]++; } cout << ans << "\n"; } }
#include <bits/stdc++.h> using namespace std; const double EPS = 1e-9; const double PI = 3.14159265359; vector<long long> primes; void GeneratingPrimes(int top) { vector<bool> p(top + 1, 1); p[0] = p[1] = 0; for (int i = 2; i <= sqrt(top); i++) { if (p[i]) { for (int j = i * i; j <= top; j += i) { p[j] = 0; } } } for (int i = 0; i < top + 1; i++) if (p[i]) primes.push_back(i); } long long gcd(long long a, long long b) { return (b == 0) ? a : gcd(b, a % b); } long long lcm(long long a, long long b) { return (a * b) / gcd(a, b); } void EXTgcd(long long a, long long b, long long& x0, long long& y0) { if (b == 0) { x0 = 1, y0 = 0; return; } EXTgcd(b, a % b, x0, y0); long long x1 = y0; long long y1 = x0 - (a / b) * (y0); y1 = y1; x0 = x1; y0 = y1; } long long power(long long n, long long p, long long mod) { if (!p) return 1; long long ans = 1; while (p > 1) { if (p & 1) ans = (ans * n) % mod; n = (n * n) % mod; p /= 2; } return (ans * n) % mod; } double dist(double a, double b, double x, double y) { return sqrt(pow(a - x, 2) + pow(b - y, 2)); } double dist3(double a, double b, double c, double x, double y, double z) { return sqrt(pow(a - x, 2) + pow(b - y, 2) + pow(c - z, 2)); } int xadd[9] = {1, -1, 0, 1, -1, 0, 1, -1, 0}; int yadd[9] = {1, -1, 0, -1, 0, 1, 0, 1, -1}; int xx[4] = {0, 1, 0, -1}; int yy[4] = {1, 0, -1, 0}; long long const N = 1e5 + 10; long long const INF = 1e18; long long const mod = 998244353; int t, n, a[N]; int main() { cin >> t; while (t--) { long long curSum = 0, ans = 0; cin >> n; for (int i = 0; i < n; i++) { char c; cin >> c; a[i] = c - '0' - 1; } map<int, long long> memoSum; memoSum[0]++; for (int i = 0; i < n; i++) { curSum += a[i]; ans += memoSum[curSum]; memoSum[curSum]++; } cout << ans << endl; } return 0; }
#include <bits/stdc++.h> using namespace std; void solve() { int n; cin >> n; string a; cin >> a; unordered_map<int, int> mp2; mp2[0]++; long long ans = 0, sum = 0; for (int i = 0; i < n; i++) { if (a[i] - '0' == 0) { sum--; } else { sum = sum + (a[i] - '0' - 1); } if (mp2.find(sum) != mp2.end()) { ans = ans + mp2[sum]; } mp2[sum]++; } cout << ans << '\n'; } int main() { ios_base::sync_with_stdio(0); cin.tie(0); int t; cin >> t; while (t--) { solve(); } }
#include <bits/stdc++.h> using namespace std; int main() { int t; cin >> t; while (t--) { int n; cin >> n; string a; cin >> a; int b[n + 2]; long long int s = 0; for (int i = 0; i < n; i++) { s += (a[i] - '0'); b[i] = s - i; } int an = 0; s = 0; for (int i = 0; i < n; i++) { s += a[i] - '0'; if (s == i + 1) an++; } sort(b, b + n); vector<long long int> c; int ss = 1; for (int i = 1; i < n; i++) { if (b[i] != b[i - 1]) { c.push_back(ss); ss = 1; } else { ss++; } } c.push_back(ss); long long int ans = 0; for (int i = 0; i < c.size(); i++) { if (c[i] > 1) { ans += (c[i] * (c[i] - 1)) / 2; } } cout << ans + an << "\n"; } return 0; }
#include <bits/stdc++.h> using namespace std; int main() { int n; while (cin >> n) { for (int x = 0; x < n; x++) { int a; cin >> a; int num[a + 1]; int sum[a + 1]; char word[a + 1]; int res[a + 1]; for (int i = 1; i <= a; i++) { cin >> word[i]; num[i] = int(word[i]) - 48; } sum[0] = 0; res[0] = 0; for (int i = 1; i <= a; i++) { sum[i] = sum[i - 1] + num[i]; res[i] = sum[i] - i; } sort(res, res + a + 1); long long int ans = 0; long long int tmp = 1; for (int i = 1; i <= a; i++) { if (res[i] == res[i - 1] && i != a) { tmp = tmp + 1; } else if (res[i] == res[i - 1] && i == a) { tmp = tmp + 1; ans = ans + ((tmp - 1) * tmp) / 2; } else { ans = ans + ((tmp - 1) * tmp) / 2; tmp = 1; } } cout << ans << "\n"; } } }
#include <bits/stdc++.h> using namespace std; void pvec(vector<long long int> &inp) { long long int n; for (n = 0; n < inp.size(); ++n) cout << inp[n] << " "; cout << endl; } void parr(long long int inp[], long long int size) { long long int n; for (n = 0; n < size; ++n) cout << inp[n] << " "; cout << endl; } int main() { long long int t, n, i, k, inp, j; string s; cin >> t; for (i = 0; i < t; ++i) { cin >> n; cin >> s; long long int arr[n], ans = 0; map<long long int, long long int> mp; map<long long int, long long int>::iterator itr; mp.insert(make_pair(0, 1)); for (k = 0; k < n; ++k) arr[k] = (int)s[k] - 48; for (k = 0; k < n; ++k) { if (k == 0) arr[k] = arr[k]; else { arr[k] = arr[k] + arr[k - 1]; } } for (k = 0; k < n; ++k) { itr = mp.find(arr[k] - (k + 1)); if (itr == mp.end()) mp.insert(make_pair(arr[k] - (k + 1), 1)); else itr->second += 1; } for (itr = mp.begin(); itr != mp.end(); ++itr) { long long int val = itr->second; ans += val * (val - 1) / 2; } cout << ans << endl; } }
#include <bits/stdc++.h> using namespace std; void _print(long long t) { cerr << t; } void _print(int t) { cerr << t; } void _print(string t) { cerr << t; } void _print(char t) { cerr << t; } void _print(long double t) { cerr << t; } void _print(double t) { cerr << t; } void _print(unsigned long long t) { cerr << t; } template <class T, class V> void _print(pair<T, V> p); template <class T> void _print(vector<T> v); template <class T> void _print(set<T> v); template <class T, class V> void _print(map<T, V> v); template <class T> void _print(multiset<T> v); template <class T, class V> void _print(pair<T, V> p) { cerr << "{"; _print(p.first); cerr << ","; _print(p.second); cerr << "}"; } template <class T> void _print(vector<T> v) { cerr << "[ "; for (T i : v) { _print(i); cerr << " "; } cerr << "]"; } template <class T> void _print(set<T> v) { cerr << "[ "; for (T i : v) { _print(i); cerr << " "; } cerr << "]"; } template <class T> void _print(multiset<T> v) { cerr << "[ "; for (T i : v) { _print(i); cerr << " "; } cerr << "]"; } template <class T, class V> void _print(map<T, V> v) { cerr << "[ "; for (auto i : v) { _print(i); cerr << " "; } cerr << "]"; } void solve() { long long t; cin >> t; while (t--) { long long n; cin >> n; string s; cin >> s; vector<long long> v(n); for (long long i = 0; i < n; ++i) { v[i] = s[i] - '0' - 1; } map<long long, long long> m; m[0] = 1; long long ans = 0, sum = 0; for (long long i = 0; i < n; ++i) { sum += v[i]; if (m.find(sum) != m.end()) ans += m[sum]; m[sum]++; } cout << ans << "\n"; } } int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL); solve(); }
#include <bits/stdc++.h> using namespace std; void solve() { int n; cin >> n; string s; cin >> s; int a[n]; unordered_map<int, int> mp; for (int i = 0; i < n; i++) { a[i] = s[i] - '0'; } mp[0]++; long long int curr_sum = 0; long long int res = 0; for (int i = 0; i < n; i++) { curr_sum += a[i]; res += mp[curr_sum - (i + 1)]++; } cout << res << '\n'; } int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); int t; cin >> t; for (int i = 0; i < t; i++) solve(); return 0; }
#include <bits/stdc++.h> using namespace std; long long gcd(long long a, long long b) { return b ? gcd(b, a % b) : a; } int t; string s; int main() { cin >> t; while (t--) { int n; cin >> n; cin >> s; vector<int> p(n + 1); for (int i = 0; i < n; i++) { p[i + 1] = p[i] + s[i] - '1'; } map<int, int> cnt; long long ans = 0; for (int i = 0; i <= n; ++i) { ans += cnt[p[i]]++; } cout << ans << endl; } return 0; }
#include <bits/stdc++.h> using namespace std; long long tc, a; char b; int main() { cin >> tc; while (tc--) { cin >> a; map<long long, long long> m; long long ps[a + 3]; long long maks = 0; long long mins = 9999999999; long long jaw = 0; m[0]++; memset(ps, 0, sizeof(ps)); for (int k = 1; k <= a; k++) { cin >> b; ps[k] = ps[k - 1] + b - '0'; m[ps[k] - k]++; maks = max(maks, ps[k] - k); mins = min(mins, ps[k] - k); } for (int k = mins; k <= maks; k++) { jaw += (m[k] * (m[k] - 1) / 2); } cout << jaw << '\n'; } }
#include <bits/stdc++.h> using namespace std; long long t, n, has; string s; map<long long, long long> dp; int main() { cin >> t; while (t--) { dp.clear(); has = 0; long long now = 0; dp[0] = 1; cin >> n >> s; for (int i = 0; i < n; i++) { now += s[i] - '0'; has += dp[now - i - 1]; dp[now - i - 1]++; } cout << has << endl; } }
#include <bits/stdc++.h> using namespace std; int main() { int test; cin >> test; while (test--) { int n; cin >> n; vector<int> arr(n); string str; cin >> str; for (int i = 0; i < n; i++) arr[i] = str[i] - '0'; long long count = 0; long long sum = 0; long long len = 0; map<long long, long long> m; m[0] = 1; long long t; for (int i = 0; i < n; i++) { sum += arr[i]; t = sum - i - 1; m[t]++; count += m[t] - 1; } cout << count << endl; } }
#include <bits/stdc++.h> using namespace std; const int N = 200100; int T, n, a[N]; char s[N]; map<int, int> m; int main() { scanf("%d", &T); for (int t = 1; t <= T; t++) { scanf("%d %s", &n, s); a[0] = 0; for (int i = 0; i < n; i++) { a[i + 1] = a[i] + s[i] - '0'; } long long res = 0; for (int i = 0; i <= n; i++) { int v = a[i] - i; if (m.count(v) != 0) { int k = m[v]; res += k; m[v] = k + 1; } else { m[v] = 1; } } printf("%lld\n", res); m.clear(); } return 0; }
#include <bits/stdc++.h> using namespace std; using namespace chrono; void _print(long long t) { cerr << t; } void _print(int t) { cerr << t; } void _print(string t) { cerr << t; } void _print(char t) { cerr << t; } void _print(long double t) { cerr << t; } void _print(double t) { cerr << t; } void _print(unsigned long long t) { cerr << t; } template <class T, class V> void _print(pair<T, V> p); template <class T> void _print(vector<T> v); template <class T> void _print(set<T> v); template <class T, class V> void _print(map<T, V> v); template <class T> void _print(multiset<T> v); template <class T, class V> void _print(pair<T, V> p) { cerr << "{"; _print(p.first); cerr << ","; _print(p.second); cerr << "}"; } template <class T> void _print(vector<T> v) { cerr << "[ "; for (T i : v) { _print(i); cerr << " "; } cerr << "]"; } template <class T> void _print(set<T> v) { cerr << "[ "; for (T i : v) { _print(i); cerr << " "; } cerr << "]"; } template <class T> void _print(multiset<T> v) { cerr << "[ "; for (T i : v) { _print(i); cerr << " "; } cerr << "]"; } template <class T, class V> void _print(map<T, V> v) { cerr << "[ "; for (auto i : v) { _print(i); cerr << " "; } cerr << "]"; } template <class T, class V> void _print(unordered_map<T, V> v) { cerr << "[ "; for (auto i : v) { _print(i); cerr << " "; } cerr << "]"; } template <class T, class V> void _print(unordered_set<T, V> v) { cerr << "[ "; for (auto i : v) { _print(i); cerr << " "; } cerr << "]"; } long long gcd(long long a, long long b) { if (b > a) { return gcd(b, a); } if (b == 0) { return a; } return gcd(b, a % b); } long long expo(long long a, long long b, long long mod) { long long res = 1; while (b > 0) { if (b & 1) res = (res * a) % mod; a = (a * a) % mod; b = b >> 1; } return res; } void extendgcd(long long a, long long b, long long *v) { if (b == 0) { v[0] = 1; v[1] = 0; v[2] = a; return; } extendgcd(b, a % b, v); long long x = v[1]; v[1] = v[0] - v[1] * (a / b); v[0] = x; return; } long long mminv(long long a, long long b) { long long arr[3]; extendgcd(a, b, arr); return arr[0]; } long long mminvprime(long long a, long long b) { return expo(a, b - 2, b); } bool revsort(long long a, long long b) { return a > b; } void swap(int &x, int &y) { int temp = x; x = y; y = temp; } long long combination(long long n, long long r, long long m, long long *fact, long long *ifact) { long long val1 = fact[n]; long long val2 = ifact[n - r]; long long val3 = ifact[r]; return (((val1 * val2) % m) * val3) % m; } void google(int t) { cout << "Case #" << t << ": "; } vector<long long> sieve(int n) { int *arr = new int[n + 1](); vector<long long> vect; for (int i = 2; i <= n; i++) if (arr[i] == 0) { vect.push_back(i); for (int j = 2 * i; j <= n; j += i) arr[j] = 1; } return vect; } long long mod_add(long long a, long long b, long long m) { a = a % m; b = b % m; return (((a + b) % m) + m) % m; } long long mod_mul(long long a, long long b, long long m) { a = a % m; b = b % m; return (((a * b) % m) + m) % m; } long long mod_sub(long long a, long long b, long long m) { a = a % m; b = b % m; return (((a - b) % m) + m) % m; } long long mod_div(long long a, long long b, long long m) { a = a % m; b = b % m; return (mod_mul(a, mminvprime(b, m), m) + m) % m; } long long phin(long long n) { long long number = n; if (n % 2 == 0) { number /= 2; while (n % 2 == 0) n /= 2; } for (long long i = 3; i <= sqrt(n); i += 2) { if (n % i == 0) { while (n % i == 0) n /= i; number = (number / i * (i - 1)); } } if (n > 1) number = (number / n * (n - 1)); return number; } void solve() { int n; cin >> n; vector<int> v(n); string s; cin >> s; for (int i = 0; i < n; i++) { int a = s[i] - '0' - 1; v[i] = a; } unordered_map<int, int> m; m[0] = 1; int curSum = 0; long long ans = 0; for (int i = 0; i < n; i++) { curSum += v[i]; ans += m[curSum]; m[curSum] += 1; } cout << ans << "\n"; } int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL); auto start1 = high_resolution_clock::now(); long long T = 1; cin >> T; for (long long t = 1; t <= T; t++) { solve(); } auto stop1 = high_resolution_clock::now(); auto duration = duration_cast<microseconds>(stop1 - start1); return 0; }
#include <bits/stdc++.h> using namespace std; int main() { int t; cin >> t; while (t--) { int n; cin >> n; vector<int> v(n); string s; cin >> s; for (int i = 0; i < n; i++) { v[i] = s[i] - '0'; } unordered_map<long long int, long long int> m; m[0] = 1; long long int count = 0; long long int sum = 0; for (int i = 0; i < n; i++) { v[i]--; sum += v[i]; count += m[sum]; m[sum]++; } cout << count << endl; } return 0; }
#include <bits/stdc++.h> using namespace std; int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL); long long int t; cin >> t; while (t--) { long long int n; cin >> n; long long int p = 0; map<long long int, long long int> occur; string s; set<long long int> occurance; cin >> s; long long int ans = 0; for (long long int i = 0; i < n; i++) { long long int d = s[i] - '0'; p += d; if (occur.count(p - (i + 1)) == 0) { occur[p - (i + 1)] = 0; } if (p == i + 1) { ans++; } occur[p - (i + 1)]++; occurance.insert(p - (i + 1)); }; for (auto x : occurance) { ans += ((occur[x] * (occur[x] - 1)) / 2); } cout << ans << endl; } return 0; }
#include <bits/stdc++.h> using namespace std; long long int countP(vector<long long int> arr, long long int n) { unordered_map<long long int, long long int> map; for (long long int i = 0; i < n; i++) map[arr[i] - i]++; long long int res = 0; for (auto x : map) { long long int cnt = x.second; res += ((cnt * (cnt - 1)) / 2); } return res; } void solve() { long long int n, ans = 0, sm = 0, x; cin >> n; string s; cin >> s; vector<long long int> v; for (long long int i = 0; i < s.length(); i++) { x = (long long int)s[i] - 48; v.push_back(x); sm += x; } vector<long long int> sum(n); sum[0] = v[0]; for (long long int i = 1; i <= n - 1; i++) { sum[i] = sum[i - 1] + v[i]; } sum.insert(sum.begin(), 0); ans += countP(sum, n + 1); cout << ans << "\n"; } int main() { int t = 1; scanf("%d", &t); while (t--) { solve(); } return 0; }
#include <bits/stdc++.h> using namespace std; long long n, t; map<long long, long long> mp; char s[100010]; signed main() { cin >> t; while (t--) { cin >> n; scanf("%s", s + 1); long long ans = 0, now = 0; mp.clear(); mp[0] = 1; for (long long i = 1; i <= n; i++) { now += (s[i] - '0'); now--; ans += mp[now]; mp[now]++; } cout << ans << "\n"; } }
#include <bits/stdc++.h> using namespace std; const int maxn = 1e5 + 20; long long int ans; int A[maxn]; void DAQ(int l, int r) { if (r - l < 2) { if (A[l] == 1) ans++; return; } int mid = (l + r) >> 1; vector<int> R; R.push_back(A[mid]); for (int i = mid + 1; i < r; i++) R.push_back(R.back() + A[i]); for (int i = 0; i < R.size(); i++) R[i] -= i + 1; sort(R.begin(), R.end()); int sum = 0; for (int i = mid - 1; i >= l; i--) { sum += A[i]; int x = mid - i - sum; ans += upper_bound(R.begin(), R.end(), x) - lower_bound(R.begin(), R.end(), x); } DAQ(l, mid); DAQ(mid, r); } void solve() { int n; cin >> n; string s; cin >> s; for (int i = 0; i < n; i++) { A[i] = s[i] - 48; } DAQ(0, n); cout << ans << "\n"; ans = 0; } int main() { ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0); int t; cin >> t; while (t--) { solve(); } return 0; }
#include <bits/stdc++.h> using namespace std; int main() { long long int t; cin >> t; while (t--) { long long int n; string str; cin >> n >> str; long long int i, j, c = 0; long long int a[n], b[n], sum[n]; for (i = 0; i < n; i++) { a[i] = str[i] - '0'; } sum[0] = a[0]; for (i = 1; i < n; i++) { sum[i] = sum[i - 1] + a[i]; } for (i = 0; i < n; i++) { b[i] = sum[i] - (i + 1); if (b[i] == 0) c++; } map<long long int, long long int> make_pair; vector<long long int> v; for (i = 0; i < n; i++) { if (make_pair[b[i]] == 0) { v.push_back(b[i]); } make_pair[b[i]]++; } for (i = 0; i < v.size(); i++) { if (make_pair[v[i]] > 1) { long long int x = make_pair[v[i]]; c += ((x * (x - 1)) / 2); } } cout << c << "\n"; } }
#include <bits/stdc++.h> using namespace std; long long INF = 1e9 + 7; int MOD = 998244353; ostream& operator<<(ostream& out, vector<int>& v) { for (int num : v) out << num << ' '; return out; } istream& operator>>(istream& in, vector<int>& v) { for (int i = 0; i < v.size(); i++) in >> v[i]; return in; } int main() { cin.tie(0); ios_base::sync_with_stdio(false); int t; cin >> t; while (t--) { int n; cin >> n; string s; cin >> s; vector<int> sums(1e6); long long ans = 0, sum = 0; for (int i = 0; i < n; i++) { int a = s[i] - '1'; sum += a; if (sum == 0) ans++; ans += sums[sum + 1e5]; sums[sum + 1e5]++; } cout << ans << '\n'; } }
#include <bits/stdc++.h> using namespace std; template <class T> void _R(T &x) { cin >> x; } void _R(int &x) { scanf("%d", &x); } void _R(int64_t &x) { scanf("%lld", &x); } void _R(double &x) { scanf("%lf", &x); } void _R(char &x) { scanf(" %c", &x); } void _R(char *x) { scanf("%s", x); } void R() {} template <class T, class... U> void R(T &head, U &...tail) { _R(head); R(tail...); } template <class T> void _W(const T &x) { cout << x; } void _W(const int &x) { printf("%d", x); } void _W(const int64_t &x) { printf("%lld", x); } void _W(const double &x) { printf("%.16f", x); } void _W(const char &x) { putchar(x); } void _W(const char *x) { printf("%s", x); } template <class T, class U> void _W(const pair<T, U> &x) { _W(x.first); putchar(' '); _W(x.second); } template <class T> void _W(const vector<T> &x) { for (auto i = x.begin(); i != x.end(); _W(*i++)) if (i != x.cbegin()) putchar(' '); } void W() {} template <class T, class... U> void W(const T &head, const U &...tail) { _W(head); putchar(sizeof...(tail) ? ' ' : '\n'); W(tail...); } int MOD = 1e9 + 7; void ADD(long long &x, long long v) { x = (x + v) % MOD; if (x < 0) x += MOD; } const int SIZE = 1 << 20; void solve() { int n; R(n); string s; R(s); map<int, int> AA; AA[0]++; int now = 0; for (int i = 0; i < (((int)(s).size())); ++i) { now += s[i] - '0' - 1; AA[now]++; } long long an = 0; for (auto &[x, y] : AA) an += y * (y - 1LL) / 2; W(an); } int main() { int ___T; scanf("%d", &___T); for (int cs = 1; cs <= ___T; cs++) { solve(); } return 0; }
#include <bits/stdc++.h> using namespace std; void solve(); int32_t main() { ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); long long int t = 1; cin >> t; while (t--) solve(); return 0; } void solve() { long long int i, j; long long int n; cin >> n; string s; cin >> s; vector<long long int> pref(n); for (long long int i = 0; i < s.length(); i++) { long long int x = s[i] - '0'; x--; pref[i] = x; } long long int sum = 0, ans = 0; map<long long int, long long int> mp; mp[0] = 1; for (long long int i = 0; i < s.length(); i++) { sum += pref[i]; ans += mp[sum]; mp[sum]++; } cout << ans << "\n"; }
#include <bits/stdc++.h> using namespace std; char a[100001]; long long b[2000001]; long long c[100001]; long long qh[100001]; long long ans = 0; template <typename T> inline void read(T &x) { x = 0; int f = 1; char c = getchar(); while (c > '9' || c < '0') { if (c == '-') f = -1; c = getchar(); } while (c <= '9' && c >= '0') { x *= 10; x = x + c - '0'; c = getchar(); } x *= f; } int main() { int T; cin >> T; for (int i = 1; i <= 100000; i++) { qh[i] = qh[i - 1] + i; } while (T--) { ans = 0; int n; cin >> n; memset(b, 0, sizeof(b)); for (int i = 1; i <= n; i++) { cin >> a[i]; c[i] = a[i] - '1'; } for (int i = 1; i <= n; i++) { c[i] += c[i - 1]; b[c[i] + 1000000]++; if (c[i] == 0) { ans += qh[b[c[i] + 1000000]]; ans -= qh[b[c[i] + 1000000] - 1]; } if (c[i] != 0) { if (b[c[i] + 1000000] >= 2) { ans += qh[b[c[i] + 1000000] - 1]; ans -= qh[b[c[i] + 1000000] - 2]; } } } cout << ans << endl; } return 0; }