제출 #239018

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
239018		VEGAnn	Mate (COCI18_mate)	C++14	80 / 100	2093 ms	19332 KiB

mate

#include <bits/stdc++.h>
#define i2 array<int,2>
#define PB push_back
#define all(x) x.begin(),x.end()
#define sz(x) ((int)x.size())
using namespace std;
typedef long long ll;
const int N = 2010;
const ll OO = 1e18;
const int md = int(1e9) + 7;
string s, st;
int n, cnt[N][26], C[N][N], ans;

int sum(int x, int y){
    x += y;
    if (x >= md)
        x -= md;
    return x;
}

int mult(int x, int y) { return (1ll * x * y) % md; }

int main(){
    ios_base::sync_with_stdio(0); cin.tie(0);

#ifdef _LOCAL
    freopen("in.txt","r",stdin);
#endif // _LOCAL

    cin >> s;
    n = sz(s);

    for (int i = 0; i < n; i++)
    for (int j = i + 1; j < n; j++)
        cnt[i][s[j] - 'a']++;

    C[0][0] = 1;

    for (int i = 1; i <= n; i++){
        C[i][0] = C[i][i] = 1;

        for (int j = 1; j < n; j++)
            C[i][j] = sum(C[i - 1][j], C[i - 1][j - 1]);
    }

    int qq; cin >> qq;

    for (; qq; qq--){
        int d; cin >> d >> st;

        d -= 2;

        int ch = (st[1] - 'a');

        ans = 0;

        for (int i = 0; i < n; i++)
            if (s[i] == st[0])
                ans = sum(ans, mult(cnt[i][ch], C[i][d]));

        cout << ans << '\n';
    }

    return 0;
}

• Subtask 1: 80 / 100