POJ1797 Heavy Transportation

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<algorithm>
 4 using namespace std;
 5 #define inf 0x3f3f3f3f
 6 const int maxn = 1005;
 7 int father[maxn];
 8 
 9 struct node{
10     int x, y, w;
11 }p[maxn*maxn]; //第一次开maxn，RE了一次
12 
13 int cmp(node A, node B)
14 {
15     return A.w > B.w; //权值从大到小排序
16 }
17 
18 int Find(int x)
19 {
20     return father[x] == x ? x : father[x] = Find(father[x]);
21 }
22 
23 void Union(int x, int y)
24 {
25     int rootx = Find(x);
26     int rooty = Find(y);
27     if(rootx != rooty) father[rootx] = rooty;
28     return ;
29 }
30 
31 int main()
32 {
33     int t, n, m, kase = 1;
34     scanf("%d", &t);
35     while(t--)
36     {
37         scanf("%d %d", &n, &m);
38         for(int i = 1; i <= n; i++) father[i] = i;
39         for(int i = 1; i <= m; i++)
40         scanf("%d %d %d", &p[i].x, &p[i].y, &p[i].w);
41         sort(p+1, p+1+m, cmp); //注意这里是p+1开始
42 
43         int ans = inf; //初始化ans为最大值
44         for(int i = 1; i <= m; i++)
45         {
46             int rootx = Find(p[i].x);
47             int rooty = Find(p[i].y);
48             if(rootx != rooty)
49             {
50                 Union(rootx, rooty);
51                 //ans保存路径中最小的权值
52                 if(p[i].w < ans) ans = p[i].w;
53                 //如果1和n已经连接，则直接跳出
54                 if(Find(1) == Find(n)) break; 
55             }
56         }
57         //注意输出格式
58         printf("Scenario #%d:\n%d\n\n", kase++, ans);
59     }
60     return 0;
61 }