find the most comfortable road

4 4
1 2 2
2 3 4
1 4 1
3 4 2
2
1 3
1 2

1
0

kruskal算法+枚举每一种情况

#include"stdio.h"
#include"string.h"
#include"stdlib.h"
#define N 205
#define M 1005
const int inf=(int)1e10;
int fa[N];
struct node
{
    int a,b,v;
}e[M];
int cmp(const void*a,const void*b)
{
    return (*(struct node*)a).v-(*(struct node*)b).v;
}
int Min(int a,int b)
{
    return a<b?a:b;
}
int Max(int a,int b)
{
    return a>b?a:b;
}
int find(int k)
{
    if(k!=fa[k])
        fa[k]=find(fa[k]);
    return fa[k];
}
int main()
{
    int n,m,i,j;
    while(scanf("%d%d",&n,&m)!=-1)
    {
        for(i=0;i<m;i++)
        {
            scanf("%d%d%d",&e[i].a,&e[i].b,&e[i].v);
        }
        qsort(e,m,sizeof(e[0]),cmp);
        int q,a,b;
        scanf("%d",&q);
        while(q--)
        {
            scanf("%d%d",&a,&b);
            int ans=inf;
            for(i=0;i<m;i++)
            {
                int min=inf,max=0;
                for(j=1;j<=n;j++)
                {
                    fa[j]=j;
                }
                for(j=i;j<m;j++)
                {
                    int f1=find(e[j].a);
                    int f2=find(e[j].b);
                    if(f1!=f2)
                    {
                        fa[f1]=f2;
                        max=Max(max,e[j].v);
                        min=Min(min,e[j].v);
                    }
                    if(find(a)==find(b))
                    {
                        ans=Min(ans,max-min);
                        break;
                    }
                }
            }
            if(ans==inf)
                printf("-1\n");
            else
                printf("%d\n",ans);
        }
    }
    return 0;
}

hdu 1598 find the most comfortable road,布布扣,bubuko.com

hdu 1598 find the most comfortable road

原文：http://blog.csdn.net/u011721440/article/details/25184267