hdu 6060 RXD and dividing

思路：判断子树节点个数和k的最小值就好了，long long 

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N=1e6+10;

int n,k;
vector<pair<int ,ll > > e[N];
ll sum;
int a[N];
void dfs(int u,int fa){
    a[u]=1;
    for(int i=0;i<e[u].size();i++){
        int v=e[u][i].first;
        if(v==fa) continue;
        dfs(v,u);
        a[u]+=a[v];
    }
        for(int i=0;i<e[u].size();i++){
            int v=e[u][i].first;
            if(v==fa) continue;
         //   cout<<e[u][i].second<<" "<<min(a[u]-1,k)<<" "<<u<<endl;
            sum+=min(a[v],k)*e[u][i].second;
        }

}
int main(){
    while(scanf("%d%d",&n,&k)!=EOF){
        for(int i=1;i<=n;i++) e[i].clear();
        memset(a,0,sizeof(a));
        int x,y,z;
        sum=0;
        for(int i=1;i<n;i++){
            scanf("%d%d%d",&x,&y,&z);
            e[x].push_back(make_pair(y,z));
            e[y].push_back(make_pair(x,z));
        }
        dfs(1,0);
        cout<<sum<<endl;
    }
}