hdu1598 依旧并查集

809773 asia2562219 E Accepted 220 KB 187 ms C++ 1786 B 2012-11-11 12:34:27 
 1 #include <cstdio>
 2 #include <cstring>
 3 #include <cstdlib>
 4 #include <algorithm>
 5 #include <iostream>
 6 using namespace std;
 7 #define MAXN 111111
 8 int rank[222],father[222];
 9 int n,m,q;
10 int maxn,minn,ans;
11 struct node
12 {
13     int x,y,speed;
14 }edge[222*222];
15 bool cmp(node n1,node n2)
16 {
17     return n1.speed > n2.speed;
18 }
19 int Find(int x)
20 {
21     if(father[x]!=x)
22     return father[x] = Find(father[x]);
23     return father[x];
24 }
25 
26 void Union(int x,int y)
27 {
28     if(x==y)return;
29     if(rank[x] > rank[y])
30         father[y] = x;
31     else
32     {
33         if(rank[x]==rank[y])
34         rank[y]++;
35         father[x] = y;
36     }
37 }
38 int main()
39 {
40     int i,j,x,y;
41     while(scanf("%d%d",&n,&m)!=EOF)
42     {
43         for(i=0;i<m;i++)
44         {
45             scanf("%d%d%d",&edge[i].x,&edge[i].y,&edge[i].speed);
46         }
47         sort(edge,edge+m,cmp);
48         scanf("%d",&q);
49         while(q--)
50         {
51             scanf("%d%d",&x,&y);
52             ans=11111111;
53             for(i=m-1;i>=0;i--)
54             {
55                 for(j=0;j<=n;j++)
56                 {
57                     rank[j]=0;
58                     father[j]=j;
59                 }
60                 bool flag=false;
61                 int temp;
62                 for(j=i;j>=0;j--)
63                 {
64                     Union(Find(edge[j].x),Find(edge[j].y));
65                     if(Find(x)==Find(y))
66                     {
67                         flag=true;
68                         temp=j;
69                         break;
70                     }
71                 }
72                 if(!flag)break;
73                 if(ans>edge[temp].speed-edge[i].speed)
74                 {
75                     ans=edge[temp].speed-edge[i].speed;
76                 }
77             }
78 
79             if(ans==11111111)ans=-1;
80             printf("%d\n",ans);
81             }
82 
83         }
84         return 0;
85 }

光棍节 下午活动去~~

posted @ 2012-11-11 12:40  TO_Asia  阅读(133)  评论(0)  编辑  收藏  举报