BZOJ 4321: queue2|动态规划

#include<cstdio>
#include<cstdlib>
#include<cmath>
#include<cstring>
#include<vector>
#include<queue>
#include<iostream>
#include<algorithm>
#include<set>
#include<map>
#define R 7777777
#define ll long long
using namespace std;
ll f[1010][1010][2];
int main()
{
int n;cin>>n;
f[1][0][0]=1;
for(int i=1;i<=n;i++) for(int j=0;j<i;j++)
{
(f[i+1][j+1][1]+=2*f[i][j][0])%=R;
(f[i+1][j-1][0]+=j*f[i][j][0])%=R;
(f[i+1][j][0]+=(i-j-1)*f[i][j][0])%=R;
(f[i+1][j+1][1]+=f[i][j][1])%=R;
(f[i+1][j][1]+=f[i][j][1])%=R;
(f[i+1][j-1][0]+=(j-1)*f[i][j][1])%=R;
(f[i+1][j][0]+=(i-j)*f[i][j][1])%=R;
}
cout<<f
[0][0]%R;
return 0;
}