結果
問題 | No.2858 Make a Palindrome |
ユーザー |
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提出日時 | 2024-08-25 15:43:04 |
言語 | C++17 (gcc 13.3.0 + boost 1.87.0) |
結果 |
AC
|
実行時間 | 718 ms / 3,000 ms |
コード長 | 2,870 bytes |
コンパイル時間 | 4,069 ms |
コンパイル使用メモリ | 254,612 KB |
最終ジャッジ日時 | 2025-02-24 01:33:57 |
ジャッジサーバーID (参考情報) |
judge1 / judge4 |
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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>using namespace std;//* ATCODER#include<atcoder/all>using namespace atcoder;typedef modint998244353 mint;//*//* BOOST MULTIPRECISION#include<boost/multiprecision/cpp_int.hpp>using namespace boost::multiprecision;//*/typedef long long ll;#define rep(i, s, n) for (int i = (int)(s); i < (int)(n); i++)#define rrep(i, s, n) for (int i = (int)(n)-1; i >= (int)(s); i--)template <typename T> bool chmin(T &a, const T &b) {if (a <= b) return false;a = b;return true;}template <typename T> bool chmax(T &a, const T &b) {if (a >= b) return false;a = b;return true;}template <typename T> T max(vector<T> &a){assert(!a.empty());T ret = a[0];for (int i=0; i<(int)a.size(); i++) chmax(ret, a[i]);return ret;}template <typename T> T min(vector<T> &a){assert(!a.empty());T ret = a[0];for (int i=0; i<(int)a.size(); i++) chmin(ret, a[i]);return ret;}template <typename T> T sum(vector<T> &a){T ret = 0;for (int i=0; i<(int)a.size(); i++) ret += a[i];return ret;}vector< int > manacher(const string &s) {vector< int > radius(s.size());int i = 0, j = 0;while(i < s.size()) {while(i - j >= 0 && i + j < s.size() && s[i - j] == s[i + j]) {++j;}radius[i] = j;int k = 1;while(i - k >= 0 && i + k < s.size() && k + radius[i - k] < j) {radius[i + k] = radius[i - k];++k;}i += k;j -= k;}return radius;}int max_odd(string s) {vector<int> targ = manacher(s);int odd = max(targ) * 2 - 1;return odd;}int max_even(string s) {string t = "";rep(i,0,(int)s.size()){t += s[i];t += '$';}t.pop_back();int even = 0;vector<int> tmp = manacher(t);for (int i=1; i<(int)tmp.size(); i+=2){even = max(even, tmp[i]/2*2);}return even;}int max_length_palindrome(string s){return max(max_even(s), max_odd(s));}void solve(){int n; cin >> n;ll m; cin >> m;string s; cin >> s;if (max_length_palindrome(s) >= m){cout << 1 << endl;return;}string t1 = s;string t2 = s;t2 += s;string t3 = s;t3 += s;t3 += s;string t4 = s;t4 += s;t4 += s;t4 += s;if (max_length_palindrome(t2) >= m){cout << 2 << endl;return;}if (max_length_palindrome(t3) >= m){cout << 3 << endl;return;}if (max_length_palindrome(t3) >= m){cout << 3 << endl;return;}if (max_length_palindrome(t2) == max_length_palindrome(t3)){cout << -1 << endl;return;}ll a1 = - max_length_palindrome(t2) + max_length_palindrome(t3);ll b1 = max_length_palindrome(t2); // 2ll f1 = (m - b1 + a1 - 1) / a1 + 2;cout << f1 << endl;/*ll a2 = - max_length_palindrome(t2) + max_length_palindrome(t4);ll b2 = max_length_palindrome(t2); // 3ll f2 = (m - b2 + a2 - 1) / a2 * 2 + 3;cout << f2 << endl;*/}int main(){int t; cin >> t;while(t--) solve();}