#include<bits/stdc++.h>
using namespace std;
const int nmax=3e2+5,mod=1e9+7,fourth=(mod+1)/4;
int dp[nmax][nmax][nmax];
int h,w;
int rec(int row,int free,int one_not_forced)
{
if(row>h)return 1;
if(dp[row][free][one_not_forced]!=-1)return dp[row][free][one_not_forced];
int ret=rec(row+1,free,one_not_forced);//do not place
//place one
//on new
if(free)ret=(ret+4LL*(free)*rec(row+1,free-1,one_not_forced+1))%mod;
//on old
if(one_not_forced)ret=(ret+1LL*fourth*one_not_forced%mod*rec(row+1,free,one_not_forced-1))%mod;
//place two
if(free>=2)ret=(ret+1LL*free*(free-1)/2*rec(row+1,free-2,one_not_forced))%mod;
dp[row][free][one_not_forced]=ret;
return ret;
}
int main()
{
memset(dp,-1,sizeof(dp));
scanf("%i%i",&h,&w);
int output=rec(1,w,0);
output=(output+mod-1)%mod;
printf("%i\n",output);
return 0;
}
Compilation message
tents.cpp: In function 'int main()':
tents.cpp:32:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%i%i",&h,&w);
~~~~~^~~~~~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
59 ms |
111352 KB |
Output is correct |
2 |
Correct |
59 ms |
111352 KB |
Output is correct |
3 |
Correct |
61 ms |
111352 KB |
Output is correct |
4 |
Correct |
59 ms |
111352 KB |
Output is correct |
5 |
Correct |
59 ms |
111352 KB |
Output is correct |
6 |
Correct |
74 ms |
111352 KB |
Output is correct |
7 |
Correct |
64 ms |
111352 KB |
Output is correct |
8 |
Correct |
71 ms |
111352 KB |
Output is correct |
9 |
Correct |
58 ms |
111352 KB |
Output is correct |
10 |
Correct |
114 ms |
111352 KB |
Output is correct |
11 |
Correct |
59 ms |
111356 KB |
Output is correct |
12 |
Correct |
255 ms |
111480 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
59 ms |
111352 KB |
Output is correct |
2 |
Correct |
59 ms |
111352 KB |
Output is correct |
3 |
Correct |
61 ms |
111352 KB |
Output is correct |
4 |
Correct |
59 ms |
111352 KB |
Output is correct |
5 |
Correct |
59 ms |
111352 KB |
Output is correct |
6 |
Correct |
74 ms |
111352 KB |
Output is correct |
7 |
Correct |
64 ms |
111352 KB |
Output is correct |
8 |
Correct |
71 ms |
111352 KB |
Output is correct |
9 |
Correct |
58 ms |
111352 KB |
Output is correct |
10 |
Correct |
114 ms |
111352 KB |
Output is correct |
11 |
Correct |
59 ms |
111356 KB |
Output is correct |
12 |
Correct |
255 ms |
111480 KB |
Output is correct |
13 |
Correct |
61 ms |
111352 KB |
Output is correct |
14 |
Incorrect |
60 ms |
111352 KB |
Output isn't correct |
15 |
Halted |
0 ms |
0 KB |
- |