mirror of
https://github.com/Kiritow/OJ-Problems-Source.git
synced 2024-03-22 13:11:29 +08:00
100 lines
2.1 KiB
C++
100 lines
2.1 KiB
C++
#include <iostream>
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#include <string.h>
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#include <math.h>
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#include <stdio.h>
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#include <algorithm>
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#include <vector>
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using namespace std;
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#define LL long long
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#define N 100010
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#define M 1000010
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vector<pair<int,int> > v[N];//定义一个pair型的主要是因为要在v[].second中储存路径权值
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struct node
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{
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int a,b,w;
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} edge[M];//储存每条边
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int father[N],vis[N];
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int n,m;
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long long ans;//记录总权值；
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bool cmp(node x,node y)
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{
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return x.w<y.w;
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}
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int finds(int x)
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{
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return father[x]==x?x:father[x]=finds(father[x]);
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}
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long long dfs(int x) //dfs递归搜索
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{
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vis[x]=1;
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//标记顶点避免死循环
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int i;
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long long nb=0,cb=0;
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int h=v[x].size();
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for(i=0;i<h;i++)
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{
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int b=v[x][i].first;
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if(!vis[b])
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{
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nb=dfs(b);
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cb+=nb;
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ans+=nb*(n-nb)*v[x][i].second;
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}
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}
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return 1+cb;
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}
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int main()
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{
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int t,i;
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long long sum;
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cin>>t;
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while(t--)
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{
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for(i=0; i<=N; i++)
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v[i].clear();
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memset(vis,0,sizeof(vis));
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ans=0;
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sum=0;
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int flag=0;
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scanf("%d%d",&n,&m);
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if(n==0||m==0)
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{
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printf("0 0.00\n");
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continue;
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}
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for(i=1; i<=n; i++)
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{
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father[i]=i;
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}
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for(i=0; i<m; i++)
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{
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scanf("%d%d%d",&edge[i].a,&edge[i].b,&edge[i].w);
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}
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sort(edge,edge+m,cmp);
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for(i=0; i<m; i++)
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{
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int fx=finds(edge[i].a);
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int fy=finds(edge[i].b);
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if(fx!=fy)
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{
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flag++;
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father[fx]=fy;
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sum+=edge[i].w;
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v[edge[i].a].push_back(make_pair(edge[i].b,edge[i].w));
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v[edge[i].b].push_back(make_pair(edge[i].a,edge[i].w));
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}
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if(flag==n-1)
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break;
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}
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for(i=1; i<=n; i++)
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{
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if(v[i].size()==1)
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break;
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}
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dfs(i);
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double y=1.0*n*(n-1)/2;
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printf("%I64d %.2lf\n",sum,(double)ans/y);
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}
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return 0;
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}
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