UVa 10034 - Freckles

 1 #include <iostream>
 2 #include <cmath>
 3 #include <cstdio>
 4 #include <cstring>
 5 #define INF 999999
 6 #define MAXN 101
 7 using namespace std;
 8 
 9 double weight[MAXN][MAXN];
10 
11 struct Point{
12     double x_;
13     double y_;
14 }FreckMap[MAXN];
15 
16 void init(int FreckNum);
17 double dist(Point last,Point now);
18 void prim(int Num);
19 
20 int main()
21 {
22     #ifndef ONLINE_JUDGE
23         freopen("D:\\acm.txt","r",stdin);
24     #endif // ONLINE_JUDGE
25     int caseNum,FreckNum;
26     scanf("%d",&caseNum);
27     while(caseNum--){
28         scanf("%d",&FreckNum);
29         for(int i = 0;i < FreckNum;i++)
30             scanf("%lf%lf",&FreckMap[i].x_,&FreckMap[i].y_);
31         init(FreckNum);
32         prim(FreckNum);
33         if(caseNum)
34             printf("\n");
35     }
36     return 0;
37 }
38 
39 void init(int FreckNum){
40     for(int i = 0;i < FreckNum;i++){
41         for(int j = 0;j < FreckNum;j++){
42             if(i == j)continue;
43             weight[i][j] = dist(FreckMap[i],FreckMap[j]);
44         }
45     }
46 }
47 double dist(Point last,Point now){
48     double dis;//暂时先不开方
49     return dis = (last.x_ - now.x_)*(last.x_ - now.x_) + (last.y_ - now.y_)*(last.y_ - now.y_) ;
50 }
51 void prim(int Num){
52     double lowcost[MAXN];
53     int joinPoint,closest[MAXN];
54     double min,pathDis = 0.0;
55     for(int i = 0;i < Num;i++){         //给lowcost[]和closets[]置初值
56         lowcost[i] = weight[0][i];
57         closest[i] = 0;
58     }
59     for(int i = 1;i < Num;i++){         //找出（n-1）个顶点
60         min = INF;
61         for(int j = 0;j < Num;j++){     //在（V——U）中找出离U最近的顶点joinPoint
62             if(lowcost[j] != 0&&lowcost[j] < min){
63                 min = lowcost[j];
64                 joinPoint = j;          //joinPoint记录最近顶点的编号
65             }
66         }
67         pathDis += sqrt(min);           //生成树的总长
68         lowcost[joinPoint] = 0;         //标记joinpoint已经加入U
69         for(int j = 0;j < Num;j++){     //修改数组lowcost和closest
70             if(weight[joinPoint][j] != 0&&weight[joinPoint][j] < lowcost[j]){
71                 lowcost[j] = weight[joinPoint][j];
72                 closest[j] = joinPoint;
73             }
74         }
75     }
76     printf("%.2lf\n",pathDis);
77 }