这题要说是最短路吧，其实更像DP，因为不需要把路径相加，而是更新为最小值。做这题最大的收获就是我才知道原来优先队列也能间接排序，自己写个cmp就行了，而且原理和sort的cmp一样。真的要感谢che学长。

 1 #include <stdio.h>
 2 #include <string.h>
 3 #include <cmath>
 4 #include <queue>
 5 #include <vector>
 6 using namespace std;
 7 int n,m=1;
 8 double d[205];
 9 bool used[205];
10 typedef struct
11 {
12     int x,y;
13 }Point;
14 Point a[205];
15 struct cmp
16 {
17     bool operator()(int a , int b)
18     {
19         return d[a] > d[b] ;
20     }
21 };
22 double dis(Point d,Point b)
23 {
24     return sqrt(double(d.x-b.x)*(d.x-b.x)+(d.y-b.y)*(d.y-b.y));
25 }
26 double max(double a,double b)
27 {
28     return a > b ?a :b ;
29 }
30 double Djstl()
31 {
32     int t,i;
33     priority_queue <int, vector<int>,cmp> q;
34     memset(used,0,sizeof(used));
35     for(i = 1; i <= n; i++)
36         d[i] = 1000000;
37     d[1] = 0;
38     q.push(1);
39     while(!q.empty())
40     {
41         t = q.top(); q.pop();
42         if(used[t]) continue;
43         used[t] = 1;
44         for(i = 1; i <= n; i++)
45         if(!used[i] && max(d[t],dis(a[t],a[i])) < d[i])
46         {
47             d[i] = max(d[t],dis(a[t],a[i]));
48             q.push(i);
49         }
50     }
51     return d[n];
52 }
53 int main()
54 {
55     int i;
56     double ans;
57     while(scanf("%d",&n),n)
58     {
59         scanf("%d%d%d%d",&a[1].x,&a[1].y,&a[n].x,&a[n].y);
60         for(i = 2; i < n; i++)
61             scanf("%d%d",&a[i].x,&a[i].y);
62         ans = Djstl();
63         printf("Scenario #%d\nFrog Distance = %.3lf\n\n",m++,ans);
64     }
65     return 0;
66 }