POJ 2485 Highways

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//题意：本题要求图中最小生成树的最长边//解题思路：直接在prim算法找最小边的过程中维护最小值//Created Author: just_sort//Created Time  : 2016/1/16 17:45//File Name     : HighWays#include <cstdio>#include <cstring>#include <iostream>using namespace std;#define Read(x) scanf("%d",&x)#define INF 0x3f3f3f3fint maze[505][505],dis[505];bool vis[505];int n;int Prim(){    int ans=0;    dis[1]=0;    for(int i=1;i<=n;i++)    {        int mark,minn=INF;        for(int j=1;j<=n;j++)        {            if(!vis[j]&&dis[j]<minn)            {                minn=dis[j],mark=j;            }        }        vis[mark]=true;        ans=max(ans,dis[mark]);        for(int j=1;j<=n;j++)        {            if(!vis[j]&&dis[j]>maze[mark][j])                dis[j]=maze[mark][j];        }    }    return ans;}int main(){    int tt;    Read(tt);    while(tt--)    {        Read(n);        memset(maze,INF,sizeof(maze));        memset(vis,false,sizeof(vis));        memset(dis,INF,sizeof(dis));        for(int i=1;i<=n;i++)            for(int j=1;j<=n;j++)                Read(maze[i][j]);        //for(int i=1;i<=n;i++)maze[i][i]=INF;        int ans=Prim();        printf("%d\n",ans);    }    return 0;}

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