poj 2421 Constructing Roads MST

来源：互联网发布：奈良吉野樱花酒淘宝编辑：程序博客网时间：2024/05/04 21:51

一开始看错题了，是有已建好的路，看成必须要建的路了，prim很水

/*author:jxylang:C/C++university:China,Xidian University**If you need to reprint,please indicate the source***/#include <iostream>#include <cstdio>#include <cstdlib>#include <cstring>#include <cmath>#define INF 1E9using namespace std;int d[101][101];int vis[101];int dis[101];int K;int main(){    int n,m;    while(~scanf("%d",&n)&&n)    {        memset(vis,0,sizeof(vis));        memset(dis,127,sizeof(dis));        int i,j,a,b;        K=1;        for(i=0;i<n;i++)         for(j=0;j<n;j++)          scanf("%d",&d[i][j]);        scanf("%d",&m);        int ans=0,Min,t;        for(i=0;i<m;i++)        {            scanf("%d%d",&a,&b);            a--,b--;            d[a][b]=d[b][a]=0;        }        int now=0;        for(i=0;i<n;i++)        {            Min=INF;            for(j=0;j<n;j++)            {                if(dis[j]>=Min||vis[j])continue;                Min=dis[j];now=j;            }            vis[now]=1;            if(now)ans+=Min;            for(j=0;j<n;j++)            {                if(vis[j])continue;                dis[j]=min(dis[j],d[now][j]);            }        }        printf("%d\n",ans);    }}