119 lines
2.2 KiB
C++
119 lines
2.2 KiB
C++
#include <bits/stdc++.h> // {{{
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// https://codeforces.com/blog/entry/96344
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#pragma GCC optimize("O2,unroll-loops")
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#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
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using namespace std;
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template <typename T>
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constexpr T MIN = std::numeric_limits<T>::min();
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template <typename T>
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constexpr T MAX = std::numeric_limits<T>::max();
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template <typename T>
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[[nodiscard]] static T sc(auto&& x) {
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return static_cast<T>(x);
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}
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template <typename T>
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[[nodiscard]] static T sz(auto&& x) {
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return static_cast<T>(x.size());
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}
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template <typename... Args>
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void pr(std::format_string<Args...> fmt, Args&&... args) {
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std::print(fmt, std::forward<Args>(args)...);
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}
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template <typename... Args>
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void pr(std::format_string<Args...> fmt) {
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std::print(fmt);
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}
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template <typename... Args>
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void prln(std::format_string<Args...> fmt, Args&&... args) {
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std::println(fmt, std::forward<Args>(args)...);
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}
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template <typename... Args>
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void prln(std::format_string<Args...> fmt) {
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std::println(fmt);
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}
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void prln() {
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std::println();
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}
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void prln(auto const& t) {
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std::println("{}", t);
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}
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using ll = long long;
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using ld = long double;
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template <typename T>
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using vec = std::vector<T>;
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template <typename T, size_t N>
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using arr = std::array<T, N>;
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#define ff first
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#define ss second
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#define eb emplace_back
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#define pb push_back
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#define all(x) (x).begin(), (x).end()
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#define rall(x) (x).rbegin(), (x).rend()
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// }}}
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void solve() {
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int n;
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cin >> n;
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string s;
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cin >> s;
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int ans = 1;
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for (int k = sz<int>(s); k >= 2; --k) {
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string S = s;
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vec<int> toggle(S.size(), 0);
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int cumulative = 0;
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for (int i = 0; i < sz<int>(S) - k; ++i) {
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cumulative += toggle[i];
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int actual = (S[i] - '0') ^ (cumulative & 1);
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if (actual == 0) {
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++cumulative;
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++toggle[i + k];
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}
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}
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int zeroes = 0;
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for (int j = sz<int>(S) - k; j < sz<int>(S); ++j) {
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cumulative += toggle[j];
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int actual = (S[j] - '0') ^ (cumulative & 1);
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zeroes += actual == 0;
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}
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if (zeroes == 0 || zeroes == k) {
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ans = k;
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break;
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}
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}
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prln("{}", ans);
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}
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int main() { // {{{
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cin.tie(nullptr)->sync_with_stdio(false);
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int t = 1;
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cin >> t;
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while (t--) {
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solve();
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}
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return 0;
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}
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// }}}
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