BZOJ2435: [Noi2011]道路修建

这种水题真是……没一次AC都不好意思见人啊

P.S. LINUX无限栈真是爽炸了… 我爱递归

 /**************************************************************
     Problem: 2435
     User: zhuohan123
     Language: C++
     Result: Accepted
     Time:5320 ms
     Memory:93192 kb
 ****************************************************************/

 #include <iostream>
 #include <cstdio>
 using namespace std;
 inline int iabs(int a){return a<?-a:a;}
 inline int getnum()
 {
     int ans=;char ch=getchar();
     while(ch<''||ch>'')ch=getchar();
     while(ch>=''&&ch<='')ans=ans*+ch-'',ch=getchar();
     return ans;
 }
 int n;
 struct point{int head,f,size;}p[];
 struct edge{int next,to,c;}g[];int gnum;
 void addedge(int from,int to,int c)
 {
     g[++gnum].to=to;g[gnum].c=c;g[gnum].next=p[from].head;p[from].head=gnum;
 }
 long long ans=;
 void dfs(int po)
 {
     p[po].size++;
     for(int i=p[po].head;i;i=g[i].next)
         if(g[i].to!=p[po].f)
         {
             p[g[i].to].f=po;
             dfs(g[i].to);
             p[po].size+=p[g[i].to].size;
             ans+=(long long)g[i].c*iabs(n-*p[g[i].to].size);
         }
 }
 int main(int argc, char *argv[])
 {
     n=getnum();
     for(int i=;i<n;i++)
     {
         int u=getnum(),v=getnum(),c=getnum();
         addedge(u,v,c);addedge(v,u,c);
     }
     dfs();
     cout<<ans<<endl;
     return ;
 }