hdu5102 枚举每条边的长度

#include <iostream>
#include <algorithm>
#include <string.h>
#include <cstdio>
#include <queue>
#include <vector>
using namespace std;
const int maxn=1000005;
typedef long long ll;
struct point{
   int L,R;
   int Rper;
   ll len;
   point(int a=0,int c=0, int d=0,ll e=0){
       L=a;  R=c; Rper=d;  len=e;
   }
};
vector<int> F[100005];
queue<point> Q;
int main()
{
    int cas=0;
    scanf("%d",&cas);
    for(int cc=1; cc<=cas; ++cc){
        int n,k;
        scanf("%d%d",&n,&k);
        for(int i=0; i<=n; ++i) F[i].clear();
       while(!Q.empty())Q.pop();
        int rea=0,frt=0;
        point t1,t2;
        for(int i=1; i<n; ++i){
            int a,b;
            scanf("%d%d",&a,&b);
            F[a].push_back(b);
            F[b].push_back(a);
            Q.push(point(a,b,a,1));
            rea++;
            Q.push(point(b,a,b,1));
            rea++;
        }
        ll ans=0;
        for(frt=0; frt<2*k; ++frt){
                t1= Q.front();
                Q.pop();
             ans=ans+t1.len;
             if(rea>=2*k) {continue;}
               int sz = F[t1.R].size();
        for(int i=0; i<sz; ++i){
                 int  to = F[t1.R ][i];
                 if(to!=t1.Rper&&rea<2*k){
                     t2.L=t1.L;
                     t2.len=t1.len+1;
                     t2.R=to;
                     t2.Rper=t1.R;
                     rea++;
                     Q.push(t2);
                 }
             }
        }
        printf("%I64d\n",ans/2);

    }
    return 0;
}