bzoj1079: [SCOI2008]着色方案

#include<cstdio>
#include<algorithm>
#include<cstring>
using namespace std;
const int mod = 1000000007;


long long f[6][16][16][16][16][16];
int c[6];
int k;

long long dfs(int x,int a,int b,int c,int d,int e) {
    long long &res = f[x][a][b][c][d][e];
    if(res!=-1) return res;
    if(a+b+c+d+e==0) return res=1;
    
    res=0;
    if(a) res+=(a-(x==2))*dfs(1,a-1,b,c,d,e);
    if(b) res+=(b-(x==3))*dfs(2,a+1,b-1,c,d,e);
    if(c) res+=(c-(x==4))*dfs(3,a,b+1,c-1,d,e);
    if(d) res+=(d-(x==5))*dfs(4,a,b,c+1,d-1,e);
    if(e) res+=(e)*dfs(5,a,b,c,d+1,e-1);
    res%=mod;
    return res;
}



int main() {
    scanf("%d",&k);
    for(int i=1,x;i<=k;i++) {
        scanf("%d",&x);
        c[x]++;    
    }
    memset(f,-1,sizeof(f));
    printf("%lld\n",dfs(0,c[1],c[2],c[3],c[4],c[5]));    
    return 0;
}