hdu 1598 find the most comfortable road

思路：快排+并查集

#include<stdio.h>
#include<algorithm>
#define inf 999999

using namespace std;
struct node
{
    int s,e,w;
}road[1005];
int xx[1005];
int cmp(node a,node b)
{
    return a.w<b.w;
}
int find(int x)
{
    while(x!=xx[x]) x=xx[x];
    return x;
}
int main()
{
    int n,m;
    while(~scanf("%d%d",&n,&m))
    {
        for(int i=0;i<m;i++)
        scanf("%d%d%d",&road[i].s,&road[i].e,&road[i].w);
        sort(road,road+m,cmp);

        int p,x,y,j;
        scanf("%d",&p);
        while(p--)
        {
            int min=inf;
            scanf("%d%d",&x,&y);
            for(int i=0;i<m;i++)
            {
                for(j=0;j<m;j++)
                xx[j]=j;

                for(j=i;j<m;j ++ )
                {
                    int a=find(road[j].s);
                    int b=find(road[j].e);
                    if(a!=b) xx[a]=xx[b];   
                    if(find(x)==find(y))
                    {
                        int t=road[j].w-road[i].w;
                        if(min>t) min=t;break;
                    }

                }
                 if(j==m) break;
            }
            if(min==inf ) puts("-1");
            else printf("%d\n",min);
        }
    }
    return 0;
}