HDU 1572 (DFS)

#include<stdio.h>
#include<string.h>
#define maxn 33
int n,k,a,mini,RK;
int mapp[maxn][maxn],w[maxn];
void dfs(int station,int coun,int dis){
    if(coun==RK){
        if(mini>dis)
            mini=dis;
    }
    for(int i=1;i<n;i++){
        if(w[i]!=0){
            w[i]=0;
            dfs(i,coun+1,dis+mapp[station][i]);
            w[i]=1;
        }
    }
}

int main(){

  while(scanf("%d",&n)){
    mini=31000;
    if(n==0) break;
    RK=0;
    memset(mapp,0,sizeof(mapp));
    memset(w,0,sizeof(w));
    for(int i=0;i<n;i++){
        for(int j=0;j<n;j++){
            scanf("%d",&mapp[i][j]);
        }
    }
   scanf("%d",&k);

    for(int i=0;i<k;i++){
      scanf("%d",&a);
       if(w[a]==0) {
        RK++;
         w[a]=1;
       }

    }
    dfs(0,0,0);

   printf("%d\n",mini);
  }
  return 0;
  }