結果
問題 | No.2858 Make a Palindrome |
ユーザー |
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提出日時 | 2024-08-25 15:21:15 |
言語 | C++23 (gcc 13.3.0 + boost 1.87.0) |
結果 |
AC
|
実行時間 | 687 ms / 3,000 ms |
コード長 | 3,095 bytes |
コンパイル時間 | 5,569 ms |
コンパイル使用メモリ | 313,568 KB |
実行使用メモリ | 6,948 KB |
最終ジャッジ日時 | 2024-08-25 15:21:39 |
合計ジャッジ時間 | 24,232 ms |
ジャッジサーバーID (参考情報) |
judge1 / judge5 |
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ファイルパターン | 結果 |
---|---|
other | AC * 40 |
ソースコード
#include <bits/stdc++.h>#include <atcoder/all>using namespace std;using namespace atcoder;//using mint = modint1000000007;//const int mod = 1000000007;using mint = modint998244353;const int mod = 998244353;//const int INF = 1e9;const long long LINF = 1e18;#define rep(i, n) for (int i = 0; i < (n); ++i)#define rep2(i,l,r)for(int i=(l);i<(r);++i)#define rrep(i, n) for (int i = (n) - 1; i >= 0; --i)#define rrep2(i,l,r)for(int i=(r) - 1;i>=(l);--i)#define all(x) (x).begin(),(x).end()#define allR(x) (x).rbegin(),(x).rend()#define P pair<int,int>template<typename A, typename B> inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; }template<typename A, typename B> inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; }int main() {ios::sync_with_stdio(false);cin.tie(nullptr);int t; cin >> t;const int base = 100;vector<mint>pow(200005);pow[0] = 1;rep2(i, 1, pow.size())pow[i] = pow[i - 1] * base;while (t--) {int n, m; cin >> n >> m;string s; cin >> s;auto t = s;reverse(all(t));long long ans = LINF;vector<mint>hs(s.size() + 1), ht(t.size() + 1);rep(i, n) {hs[i + 1] = hs[i] + pow[i] * (s[i] - 'a' + 1);ht[i + 1] = ht[i] + pow[i] * (t[i] - 'a' + 1);}//rep(i, n + 1) {// cout << i << " " << hs[i].val() << endl;//}// idxからxとるauto calcHash = [&](int idx, int sz, int type)->mint {int h = min(sz, n - idx);int b = ((sz - h) / n) * n;int t = sz - h - b;//cout << idx << " " << sz << endl;//cout << h << " " << b << " " << t << endl;mint hash = 0;if (h) {mint sub = 0;if (0 == type)sub = (hs[idx + h] - hs[idx]) / pow[idx];else sub = (ht[idx + h] - ht[idx]) / pow[idx];hash += sub;//cout << sub.val() << endl;}if (b) {mint sub = 0;if (0 == type) sub = hs[n] * (pow[n].pow(b / n) - 1) / (pow[n] - 1) * pow[h];else sub = ht[n] * (pow[n].pow(b / n) - 1) / (pow[n] - 1) * pow[h];hash += sub;}if (t) {mint sub = 0;if (0 == type) sub = pow_mod(base, h + b, mod)*hs[t];else sub = pow_mod(base, h + b, mod)*ht[t];hash += sub;}return hash;};rep(i, n) {int sz = (m) / 2;int iR = (i + 1) % n;mint hR = calcHash(iR, sz, 0);int iL = (i - 1 + n) % n;iL = n - 1 - iL;mint hL = calcHash(iL, sz, 1);if (hR != hL)continue;int tmp = 1;int l = sz - i;if (l > 0)tmp += (l + n - 1) / n;int r = sz - (n - 1 - i);//???if (r > 0)tmp += (r + n - 1) / n;chmin(ans, tmp);}rep(i, n) {int sz = (m + 1) / 2;int iR = (i + 0) % n;mint hR = calcHash(iR, sz, 0);int iL = (i - 1 + n) % n;iL = n - 1 - iL;mint hL = calcHash(iL, sz, 1);if (hR != hL)continue;int tmp = 0 != i;int l = sz - i;int r = 0 == i ? sz : sz - (n - i);//cout << l << " " << r << endl;if (l > 0)tmp += (l + n - 1) / n;if (r > 0)tmp += (r + n - 1) / n;//cout << i << endl;chmin(ans, tmp);}if (LINF == ans)ans = -1;cout << ans << endl;}return 0;}