Submission #1294887

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Source Code Expand

#include<iostream>
#include<vector>
#include<iomanip>
#include<algorithm>
using namespace std;

vector<int> G[1<<18];
double dp [1<<18];
double dp2 [1<<18];

double dfs(int u,int p) {
    int cnt = 0;
    double ans = 0;
    for(int i = 0; i < G[u].size(); i ++) {
        if (G[u][i] == p) continue;
        ans += dfs(G[u][i], u) + 1;
        cnt ++;
    }
    return dp[u] = cnt ? ans / cnt : 1;
}

void dfs2(int u, int p, double a) {
    double ans=0;
    for(int i=0;i<G[u].size();i++)
    {
        if(G[u][i]==p)ans+=a;
        else ans+=dp[G[u][i]];
    }
    dp2[u] = ans/G[u].size();
    for(int i=0;i<G[u].size();i++)
    {
        if(G[u][i]==p)continue;
        dfs2(G[u][i],u, 1+(ans-dp[G[u][i]])/max(1,(int)G[u].size()-1));
    }
}

int main()
{
    int n;
    cin>>n;
    int u,v;
    for(int i = 1; i < n; i ++) {
        cin >> u >> v;
        G[u].push_back(v);
        G[v].push_back(u);
    }
    dfs(1, 0);
    dfs2(1, 0, 0);
    for(int i = 1; i <= n; i ++) {
        cout << setprecision(12) << dp2[i] << endl;
    }
    return 0;
}

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