#include <iostream>
#include <vector>
#include <set>
#include <cstring>
#define DIM 2010
#define MOD 1000000007
using namespace std;
//ifstream cin ("date.in");
//ofstream cout ("date.out");
int v[DIM],c[DIM][DIM],f[DIM],dp[DIM][30][30],a[DIM][30];
char s[DIM],l1,l2;
int n,i,j,x,y,q,lg;
int main (){
cin>>s+1;
n = strlen(s+1);
for (i=1;i<=n;i++)
v[i] = s[i] - 'a' + 1;
c[0][0] = c[1][0] = c[1][1] = 1;
for (i=2;i<=n;i++){
c[i][0] = 1;
for (j=1;j<=i;j++){
c[i][j] = c[i-1][j] + c[i-1][j-1];
if (c[i][j] >= MOD)
c[i][j] -= MOD;
}}
/// a[i][x] - in cate moduri pot selecta s[i],j (am nevoie sa stiu pozitia primului)
for (i=1;i<=n;i++)
for (j=i+1;j<=n;j++)
a[i][v[j]]++;
/// dp[i][x][y] - cate siruri de lungime i care se termina cu xy pot obtine
for (lg=2;lg<=n;lg++){
for (i=lg-1;i<=n;i++){
x = v[i];
for (y=1;y<=26;y++){
dp[lg][x][y] = dp[lg][x][y]+1LL*a[i][y]*c[i-1][lg-2]%MOD;
if (dp[lg][x][y] >= MOD)
dp[lg][x][y] -= MOD;
}}}
cin>>q;
for (;q--;){
cin>>lg>>l1>>l2;
cout<<dp[lg][l1-'a'+1][l2-'a'+1]<<"\n";
}
return 0;
}
Compilation message
mate.cpp: In function 'int main()':
mate.cpp:16:11: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
cin>>s+1;
~^~
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
89 ms |
760 KB |
Output is correct |
2 |
Correct |
60 ms |
760 KB |
Output is correct |
3 |
Correct |
69 ms |
760 KB |
Output is correct |
4 |
Correct |
117 ms |
824 KB |
Output is correct |
5 |
Correct |
422 ms |
3064 KB |
Output is correct |
6 |
Correct |
473 ms |
2936 KB |
Output is correct |
7 |
Correct |
369 ms |
2908 KB |
Output is correct |
8 |
Correct |
328 ms |
2680 KB |
Output is correct |
9 |
Execution timed out |
2036 ms |
26652 KB |
Time limit exceeded |
10 |
Execution timed out |
2064 ms |
26544 KB |
Time limit exceeded |