洛谷P1446 [HNOI2008]Cards

置换群+dp

 #include<cstdio>
 #include<cstdlib>
 #include<algorithm>
 #include<cstring>
 #include<vector>
 #include<cmath>
 #define MAXN 65
 #define ll long long
 #define pb push_back
 #define ft first
 #define sc second
 #define mp make_pair
 using namespace std;
 int Inv(int a,int p){
     int b=p-;
     int ret=;
     while(b){
         if(b&){
             ret=1LL*ret*a%p;
         }
         a=1LL*a*a%p;
         b>>=;
     }
     return ret;
 }
 int sr,sb,sg,n,m,MOD;
 int a[MAXN][MAXN];
 int f[][][];
 int b[MAXN],d[MAXN];
 int calc(int x){
     memset(b,,sizeof(b));
     memset(d,,sizeof(d));
     int cnt=;
     for(int i=;i<=n;i++){
         if(!b[i]){
             cnt++;
             for(int j=i;!b[j];j=a[x][j]){
                 d[cnt]++;
                 b[j]=;
             }
         }
     }
     memset(f,,sizeof(f));
     f[][][]=;
     for(int h=;h<=cnt;h++){
         for(int i=sr;i>=;i--){
             for(int j=sb;j>=;j--){
                 for(int k=sg;k>=;k--){
                     if(i>=d[h])(f[i][j][k]+=f[i-d[h]][j][k])%=MOD;
                     if(j>=d[h])(f[i][j][k]+=f[i][j-d[h]][k])%=MOD;
                     if(k>=d[h])(f[i][j][k]+=f[i][j][k-d[h]])%=MOD;
                 }
             }
         }
     }
     return f[sr][sb][sg];
 }
 int main()
 {
 //    freopen("data.in","r",stdin);
     scanf("%d%d%d%d%d",&sr,&sb,&sg,&m,&MOD);
     n=sr+sb+sg;
     int t;
     for(int i=;i<=m;i++){
         for(int j=;j<=n;j++){
             scanf("%d",&t);
             a[i][t]=j;
         }
     }
     m++;
     for(int i=;i<=n;i++)a[m][i]=i;
     int ans=;
     for(int i=;i<=m;i++){
         ans+=calc(i);
         ans%=MOD;
     }
     ans=1LL*ans*Inv(m,MOD)%MOD;
     printf("%d\n",ans);
     return ;
 }