Submission #1259436

#	Time	Username	Problem	Language	Result	Execution time	Memory
1259436		newsboy	Necklace (Subtask 4) (BOI19_necklace4)	C++20	15 / 15	210 ms	536 KiB

necklace

#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <iomanip>
#include <set>
#include <map>
#include <numeric>
#include <unordered_set>
#include <unordered_map>
#include <bitset>
#include <climits>
#include <queue>
#include <deque>
#include <stack>
#include <cmath>
#include <tuple>
#include <cassert>
#include <array>
#include <list>
#include <random>
#include <initializer_list>
#include <chrono>
using namespace std;
using i64 = long long;
using u64 = unsigned long long;

vector<int> pi1(6002), pi2(6002);

void work(string& s, vector<int>& pi) {
    for (int i = 1; i < s.size(); i++) {
        int j = pi[i - 1];
        while (j > 0 && s[i] != s[j]) {
            j = pi[j - 1];
        }
        if (s[i] == s[j]) {
            j++;
        }
        pi[i] = j;
    }
}

string R1, R2, T1;

tuple<int, int, int> solve(string s, string t, bool r) {
    int n = s.size();
    int m = t.size();
    T1 = t;
    reverse(T1.begin(), T1.end());
    R1 = "?" + T1;
    R2 = s + "?" + t;
    int res = 0;
    int a = -1, b = -1;
    for (int i = 0; i < n; i++) {
        R1.insert(R1.begin(), s[i]);
        R2.erase(R2.begin());
        work(R1, pi1);
        work(R2, pi2);
        for (int j = -1; j < m; j++) {
            int x = pi1[i + m - j];
            int y = pi2[n - i + j];
            if (x + y > res) {
                res = x + y;
                a = (r ? n - (i + y) - 1 : i - x + 1);
                b = j - y + 1;
            }
        }
    }
    return {res, a, b};
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    string s, t;
    cin >> s >> t;
    T1 = t;
    reverse(T1.begin(), T1.end());
    tuple<int, int, int> ans = solve(s, t, 0);
    reverse(s.begin(), s.end());
    ans = std::max(ans, solve(s, t, 1));
    cout << get<0>(ans) << '\n';
    cout << get<1>(ans) << " " << get<2>(ans) << '\n';
}

• Subtask 1: 15 / 15