diff --git a/HDOJ/5723_yuanbo123.cpp b/HDOJ/5723_yuanbo123.cpp
new file mode 100644
index 0000000..8a8a81b
--- /dev/null
+++ b/HDOJ/5723_yuanbo123.cpp
@@ -0,0 +1,99 @@
+#include <iostream>
+#include <string.h>
+#include <math.h>
+#include <stdio.h>
+#include <algorithm>
+#include <vector>
+using namespace std;
+#define LL long  long
+#define N 100010
+#define M 1000010
+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
+struct node
+{
+    int a,b,w;
+} edge[M];//储存每条边
+int father[N],vis[N];
+int n,m;
+long long  ans;//记录总权值；
+bool cmp(node x,node y)
+{
+    return x.w<y.w;
+}
+int finds(int x)
+{
+    return father[x]==x?x:father[x]=finds(father[x]);
+}
+long long dfs(int x) //dfs递归搜索
+{
+    vis[x]=1;
+    //标记顶点避免死循环
+    int  i;
+    long long nb=0,cb=0;
+    int h=v[x].size();
+    for(i=0;i<h;i++)
+    {
+        int b=v[x][i].first;
+        if(!vis[b])
+        {
+            nb=dfs(b);
+            cb+=nb;
+            ans+=nb*(n-nb)*v[x][i].second;
+        }
+    }
+    return 1+cb;
+}
+int main()
+{
+    int t,i;
+    long long sum;
+    cin>>t;
+    while(t--)
+    {
+        for(i=0; i<=N; i++)
+            v[i].clear();
+        memset(vis,0,sizeof(vis));
+        ans=0;
+        sum=0;
+        int flag=0;
+        scanf("%d%d",&n,&m);
+        if(n==0||m==0)
+        {
+            printf("0 0.00\n");
+            continue;
+        }
+        for(i=1; i<=n; i++)
+        {
+            father[i]=i;
+        }
+        for(i=0; i<m; i++)
+        {
+            scanf("%d%d%d",&edge[i].a,&edge[i].b,&edge[i].w);
+        }
+        sort(edge,edge+m,cmp);
+        for(i=0; i<m; i++)
+        {
+            int fx=finds(edge[i].a);
+            int fy=finds(edge[i].b);
+            if(fx!=fy)
+            {
+                flag++;
+                father[fx]=fy;
+                sum+=edge[i].w;
+                v[edge[i].a].push_back(make_pair(edge[i].b,edge[i].w));
+                v[edge[i].b].push_back(make_pair(edge[i].a,edge[i].w));
+            }
+            if(flag==n-1)
+                break;
+        }
+        for(i=1; i<=n; i++)
+        {
+            if(v[i].size()==1)
+                break;
+        }
+        dfs(i);
+        double y=1.0*n*(n-1)/2;
+        printf("%I64d %.2lf\n",sum,(double)ans/y);
+    }
+    return 0;
+}