Highways---poj1751最小生成树

#include<stdio.h>
#include<string.h>
#include<map>
#include<iostream>
#include<algorithm>
#include<math.h>
#define N 1100
#define INF 0xfffffff

using namespace std;

int vis
, n, pre
;//pre[i]记录的是i的父节点；
double maps

,dist
;

void Prim(int start)
{
vis[start] = 1;
for(int i=1; i<=n; i++)
{
dist[i] = maps[start][i];
pre[i] = start;
}
for(int i=1; i<=n; i++)
{
double Min = INF;
int index = -1;
for(int j = 1; j <= n; j++)
{
if(vis[j]==0 && Min>dist[j])
{
Min = dist[j];
index = j;
}
}
if(index == -1) break;
if(Min != 0)
printf("%d %d\n", pre[index],index);
vis[index] = 1;
for(int j=1; j<=n; j++)
{
if(vis[j]==0 && dist[j] > maps[index][j])
dist[j] = maps[index][j], pre[j] = index;
}
}
}

struct node
{
int x, y;
}a
;

void Init()
{
for(int i=0;i<=n;i++)
{
pre[i] = i;
vis[i] = 0;
dist[i] = INF;
for(int j=0; j<=n; j++)
maps[i][j] = INF;
maps[i][i] = 0;
}
}

int main()
{
int i, j, x, y, m;
double d;
while(scanf("%d", &n)!=EOF)
{
Init();
memset(a,0,sizeof(a));
for(i=1;i<=n;i++)
scanf("%d%d", &a[i].x, &a[i].y);
for(i=1; i<=n; i++)
{
for(j=i+1; j<=n; j++)
{
d = sqrt((a[i].x-a[j].x)*(a[i].x-a[j].x)+(a[i].y-a[j].y)*(a[i].y-a[j].y));
maps[i][j] = maps[j][i] = d;
}
}
scanf("%d", &m);
for(i=0; i<m; i++)
{
scanf("%d%d", &x,&y);
maps[x][y] = maps[y][x] = 0; //把已知边的权值置为0；
}
Prim(1);
}
return 0;
}