HDU 5001-Walk（概率dp）

#include <map>
#include <set>
#include <list>
#include <cmath>
#include <queue>
#include <stack>
#include <cstdio>
#include <vector>
#include <string>
#include <cctype>
#include <complex>
#include <cassert>
#include <utility>
#include <cstring>
#include <cstdlib>
#include <iostream>
#include <algorithm>
using namespace std;
typedef pair<int,int> PII;
typedef long long ll;
#define lson l,m,rt<<1
#define pi acos(-1.0)
#define rson m+1,r,rt<<11
#define All 1,N,1
#define read freopen("in.txt", "r", stdin)
const ll  INFll = 0x3f3f3f3f3f3f3f3fLL;
const int INF= 0x7ffffff;
const int mod =  1000000007;
vector<int>e[55];
int n,m,d;
double dp[55][10010];
void solve(){
    for(int i=1;i<=n;++i){
        memset(dp,0,sizeof(dp));
        for(int p=1;p<=n;++p)
            dp[p][0]=1.0/n;
        for(int j=0;j<d;++j){
            for(int k=1;k<=n;++k){
                if(k==i)continue;
                for(int l=0;l<e[k].size();++l){
                    if(e[k][l]==i)continue;
                    dp[e[k][l]][j+1]+=dp[k][j]*1.0/e[k].size();
                }
            }
        }
        double total=0.0;
        for(int j=1;j<=n;++j)
            if(j!=i)
            total+=dp[j][d];
        printf("%.10lf\n",total);
    }
}
int main()
{
    int t;
    scanf("%d",&t);
    while(t--){
        scanf("%d%d%d",&n,&m,&d);
        int u,v;
        for(int i=1;i<=n;++i)
            e[i].clear();
        while(m--){
            scanf("%d%d",&u,&v);
            e[u].push_back(v);
            e[v].push_back(u);
        }
        solve();
    }
return 0;
}