最小生成树之PRIM-O（n^2)

#include<stdio.h>#include<string.h>#include<stdlib.h>const int maxn=1010,maxm=10010,INF=1000000000;int a[maxn][maxn],d[maxn],p[maxn];int main(){#ifndef ONLINE_JUDGEfreopen("prim.in","r",stdin);freopen("prim.out","w",stdout);#endifint i,j,k,m,n,s;int x,y,w,ans=0,min;scanf("%d%d",&n,&m);for(i=1;i<=n;i++)d[i]=INF;for(i=1;i<=m;i++){scanf("%d%d%d",&x,&y,&w);a[x][y]=w;a[y][x]=w;}d[1]=0;for(i=1;i<=n;i++){min=INF;for(j=1;j<=n;j++)if(!p[j] && d[j]<min){min=d[j];k=j;}p[k]=1;ans+=d[k];for(j=1;j<=n;j++)if(a[k][j] && d[j]>a[k][j])d[j]=a[k][j];}printf("%d\n",ans);return 0;}