poj 2485 秒杀

就是求最小生成树中那条最大的边。。。。

#include<cstdio>
#include<cstdlib>
#include<iostream>
#include<algorithm>
#include<vector>
#include<cstring>

using namespace std;

#define MAX 65550
int map[505][505];
int dis[505];
bool s[505];

int prim(int n)
{
    for(int i=0; i<n; i++)
    for(int j=0; j<n; j++)
    scanf("%d",&map[i][j]);
    s[0] = true;
    for(int j =1; j<n; j++)
    {
      dis[j] = map[0][j];
      s[j] = false;
    }
    int ans = 0;
    for(int i=1; i<n; i++)
    {
       int min = MAX, rec;
       for(int j=0; j<n; j++)
       if(!s[j]&&dis[j]<min)
       {
        min = dis[j];
        rec = j;
       }
       s[rec] = true;
       if(ans<min&&min!=MAX) ans = min;
       for(int j =0; j<n; j++)
       if(!s[j]&&dis[j]>map[rec][j])
       dis[j] = map[rec][j];
    }
 printf("%d\n",ans);
}
int main()
{
    int ca, n;
    scanf("%d",&ca);
    while(ca--)
    {
      scanf("%d",&n);
      prim(n);
    }
   system("pause");
   return 0;
}

刚又试了下另一个算法，不过一直提示runtime error 。。。。不知道怎么搞的。。

#include<cstdio>
#include<cstdlib>
#include<iostream>
#include<algorithm>
#include<vector>
#include<cstring>
using namespace std;

#define MAX 65550
typedef struct node
{
  int c1, c2, cost;
}node;
node rode[1200];
int father[505];
int compare(const node &a, const node &b)
{
    return a.cost<b.cost;
}
int init()
{
    for(int i=0; i<505; i++)
    father[i] = i;
    return 1;
}
int find(int n)
{
   if(n!=father[n])
   {
    father[n] = find(father[n]);
    }
    return father[n];
}
int megre(int n1, int n2)
{
    int a = find(n1);
    int b = find(n2);
    if(a==b) return 0;
    if(a<b)father[n1] = n2;
    else father[n2] = n1;
    return 1;
}
void kurscal(int n)
{
     init();
    int k =0;
    for(int i=0; i<n; i++)
    for(int j=0; j<n; j++)
    {
     rode[k].c1 = i;
     rode[k].c2 = j;
    scanf("%d",&rode[k].cost);
    if(i==j) rode[k].cost = MAX;
    k++; 
    }
    sort(rode,rode+k,compare);
    int ans =0;
    for(int i=0; i<k; i++)
    {
            if(megre(rode[i].c1,rode[i].c2))
            ans = rode[i].cost;
    }
    printf("%d\n",ans);
}
int main()
{
    int ca, n;
    scanf("%d",&ca);
    while(ca--)
    {
      scanf("%d",&n);
      kurscal(n);
    }
   system("pause");
   return 0;
}