제출 #239014

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
239014		kartel	Mate (COCI18_mate)	C++14	80 / 100	2090 ms	4072 KiB

mate

#include <bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
#define in(x) freopen(x, "r", stdin)
#define out(x) freopen(x, "w", stdout)
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("-O3")
#define F first
#define S second
#define pb push_back
#define N +100500
#define M ll(1e9 + 7)
#define sz(x) (int)x.size()
#define re return
#define oo ll(1e9)
#define el '\n'
#define pii pair <int, int>
using namespace std;
//using namespace __gnu_pbds;
//typedef tree <int, null_type, less_equal <int> , rb_tree_tag, tree_order_statistics_node_update> ordered_set;
typedef long long ll;
typedef long double ld;

int sf[N][26], i, n, q, len, fc[N], j, ans = 0;
string s, t;

int sum(int x, int y) {return (x + y) % M;}
int mult(int x, int y) {return (x * 1ll * y) % M;}

int bp(int x, int y)
{
    if (y == 0) return 1;
    if (y % 2) return (mult(x, bp(x, y - 1)));
    int a = bp(x, y / 2);
    return mult(a, a);
}

int C(int k, int n)
{
    return mult(fc[n], bp(mult(fc[k], fc[n - k]), M - 2));
}

int main()
{
    srand(time(0));
    ios_base::sync_with_stdio(0);
    iostream::sync_with_stdio(0);
    ios::sync_with_stdio(0);
    cin.tie(NULL);
    cout.tie(NULL);

//    in("input.txt");
//    out("output.txt");

    cin >> s;
    cin >> q;

    n = sz(s);

    for (i = n - 1; i >= 0; i--)
    {
        for (j = 0; j < 26; j++) sf[i][j] = sf[i + 1][j];
        sf[i][s[i] - 'a']++;
    }

    fc[0] = 1;
    for (i = 1; i <= n; i++) fc[i] = mult(fc[i - 1], i);

    while (q--)
    {
        cin >> len >> t;

        ans = 0;

        for (i = len - 2; i < n; i++)
        {
            if (s[i] == t[0])
            {
                ans = sum(ans, mult(C(len - 2, i), sf[i + 1][t[1] - 'a']));
            }
        }
        cout << ans << el;
    }
}

/*
8 8
...).).*
*....)..
.)*(..).
(*)((...
.)).)(..
.)(.)..(
...).(.*
M.......
*/
//
//110000
//1100

• Subtask 1: 80 / 100