#include <bits/stdc++.h>
using namespace std;
const int maxn = 2e3 + 10, mod = 1e9 + 7;
long long dp[maxn][maxn] , f[maxn] , invf[maxn] , anss;
long long power(int a , int b){
if(b == 0){
return 1;
}
anss = power(a , b/2);
anss *= anss;
anss %= mod;
if(b & 1){
anss *= a;
anss %= mod;
}
return anss;
}
long long c(int n , int k){
if(k > n){
return 0;
}
return f[n] * invf[k] % mod * invf[n - k] % mod;
}
int main(){
int n , k , cnt = 1 , sizee;
string a[maxn];
bool mark[maxn] , markk[maxn];
vector <int> v;
cin >> n >> k;
for(int i=1 ; i<=n ; i++){
cin >> a[i];
}
for(int i=1 ; i<=n ; i++){
sizee = a[i].size();
for(int j = 0 ; j<sizee ; j++){
mark[a[i][j] - 'a'] = true;
}
if(!markk[i]){
for(int j = 1 ; j<=n ; j++){
bool x = true;
if(!markk[j] && j != i){
int sizeee = a[j].size();
for(int m = 0 ; m<sizee ; m++){
if(!mark[a[j][m] - 'a'] || sizeee != sizee){
x = false;
break;
}
}
if(x){
cnt++;
markk[j] = true;
}
}
}
v.push_back(cnt);
markk[i] = true;
}
sizee = a[i].size();
for(int j = 0 ; j<sizee ; j++){
mark[a[i][j] - 'a'] = false;
}
cnt = 1;
}
f[0] = invf[0] = 1;
for(int i=1 ; i<maxn ; i++){
f[i] = f[i-1] * i;
f[i] %= mod;
invf[i] = power(f[i] , mod - 2);
}
sizee = v.size();
dp[0][0] = 1;
for(int i=1 ; i<=sizee ; i++){
for(int j=0 ; j<=k ; j++){
for(int m = 0 ; m <= v[i - 1] ; m++){
if(c(m , 2) <= j){
dp[i][j] = dp[i][j] + (dp[i - 1][j - c(m , 2)] * c(v[i-1] , m) % mod) % mod;
dp[i][j] %= mod;
}
}
}
}
sizee = v.size();
cout << dp[sizee][k];
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
340 KB |
Output is correct |
2 |
Correct |
1 ms |
340 KB |
Output is correct |
3 |
Correct |
1 ms |
340 KB |
Output is correct |
4 |
Correct |
1 ms |
340 KB |
Output is correct |
5 |
Correct |
1 ms |
340 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
596 KB |
Output is correct |
2 |
Correct |
5 ms |
1620 KB |
Output is correct |
3 |
Correct |
2 ms |
468 KB |
Output is correct |
4 |
Correct |
6 ms |
1660 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
340 KB |
Output is correct |
2 |
Correct |
1 ms |
340 KB |
Output is correct |
3 |
Correct |
1 ms |
340 KB |
Output is correct |
4 |
Correct |
1 ms |
340 KB |
Output is correct |
5 |
Correct |
1 ms |
340 KB |
Output is correct |
6 |
Correct |
2 ms |
596 KB |
Output is correct |
7 |
Correct |
5 ms |
1620 KB |
Output is correct |
8 |
Correct |
2 ms |
468 KB |
Output is correct |
9 |
Correct |
6 ms |
1660 KB |
Output is correct |
10 |
Incorrect |
5 ms |
2004 KB |
Output isn't correct |
11 |
Halted |
0 ms |
0 KB |
- |