UVA1218 Perfect Service

Time Limit: 3000MS

64bit IO Format: %lld & %llu

 /*by SilverN*/
 #include<iostream>
 #include<algorithm>
 #include<cstring>
 #include<cstdio>
 #include<cmath>
 #include<vector>
 #include<queue>
 using namespace std;
 const int mxn=;
 vector<int>e[mxn];
 int f[mxn][];
 int vis[mxn];
 int n;
 void dp(int u){
     int i,j;
     vis[u]=;
     f[u][]=;f[u][]=;f[u][]=mxn;
     queue<int>q;
     for(i=;i<e[u].size();i++){
         int v=e[u][i];
         if(!vis[v]){
             dp(v);
             q.push(v);
             f[u][]+=min(f[v][],f[v][]);
             f[u][]+=f[v][];
         }
     }
     while(!q.empty()){
         f[u][]=min(f[u][],f[u][]-f[q.front()][]+f[q.front()][]);
         q.pop();
     }
     return;
 }
 int main(){
     int i,j;
     while(scanf("%d",&n) && n!=-){
         if(!n)continue;
         memset(f,,sizeof f);
         memset(vis,,sizeof vis);
         for(i=;i<=n;i++) e[i].clear();
         int x,y;
         for(i=;i<n;i++){
             scanf("%d%d",&x,&y);
             e[x].push_back(y);
             e[y].push_back(x);
         }
         dp();
         printf("%d\n",min(f[][],f[][]));
     }
     return ;
 }