1589 Find The Most Comfortable Road

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<algorithm>
 4 
 5 using namespace std;
 6 
 7 typedef struct {
 8     int a,b,c;
 9 } node;
10 node a[1001];
11 
12 bool op(node a,node b)
13 {
14     return a.c<b.c;
15 }
16 
17 int father[201];
18 
19 void clean_father(int n)
20 {
21     for (int i=1;i<=n;i++) father[i]=i;
22 }
23 
24 int getfather(int x)
25 {
26     if (father[x]!=x) father[x]=getfather(father[x]);
27     return father[x];
28 }
29 
30 void link(int x,int y)
31 {
32     father[getfather(x)]=getfather(y);
33 }
34 
35 int main()
36 {
37     int n,m;
38     while (scanf("%d%d",&n,&m)!=EOF)
39     {
40         for (int i=1;i<=m;i++) scanf("%d%d%d",&a[i].a,&a[i].b,&a[i].c);
41         sort(&a[1],&a[m+1],op);
42         
43         int q;
44         scanf("%d",&q);
45         for (int i=1;i<=q;i++)
46         {
47             int t1,t2;
48             scanf("%d%d",&t1,&t2);
49             
50             int minn,maxn,ans=2147483647;
51             for (int j=1;j<=m;j++)
52             {
53                 minn=2147483647;
54                 maxn=0;
55                 clean_father(n);
56                 for (int k=j;k<=m;k++)
57                 if (getfather(a[k].a)!=getfather(a[k].b))
58                 {
59                     link(a[k].a,a[k].b);
60                     if (minn>a[k].c) minn=a[k].c;
61                     if (maxn<a[k].c) maxn=a[k].c;
62                     if (maxn-minn>ans) break;
63                     if (getfather(t1)==getfather(t2))
64                     {
65                         if (ans>maxn-minn)
66                         {
67                             ans=maxn-minn;
68                             break;
69                         }
70                     }
71                 }
72             }
73             
74             if (ans!=2147483647) printf("%d\n",ans);
75             else printf("-1\n");
76         }
77     }
78     
79     return 0;
80 }