#include <bits/stdc++.h>
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("-O3")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("fast-math")
#pragma GCC optimize("no-stack-protector")
#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, C[N][N];
ll cnt[N][26], 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]) {
if (cnt[i][ch] == 0) break;
(ans += cnt[i][ch] * C[i][d]) %= md;
}
cout << ans << '\n';
}
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
11 ms |
640 KB |
Output is correct |
2 |
Correct |
9 ms |
640 KB |
Output is correct |
3 |
Correct |
10 ms |
640 KB |
Output is correct |
4 |
Correct |
18 ms |
640 KB |
Output is correct |
5 |
Correct |
55 ms |
2296 KB |
Output is correct |
6 |
Correct |
56 ms |
2296 KB |
Output is correct |
7 |
Correct |
45 ms |
2168 KB |
Output is correct |
8 |
Correct |
42 ms |
2048 KB |
Output is correct |
9 |
Execution timed out |
2083 ms |
21016 KB |
Time limit exceeded |
10 |
Execution timed out |
2089 ms |
20848 KB |
Time limit exceeded |