UVA 216 - Getting in Line

连接是：http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=152

哟我AC了喔.就是用回溯法把每一种可能都找出来，然后看哪个最小。

View Code 
 1 #include <iostream>
 2 #include <cmath>
 3 using namespace std;
 4 
 5 const int MAXNUM = 8;
 6 struct Point{
 7     int x;
 8     int y;
 9 };
10 
11 bool visit[MAXNUM];
12 Point node[MAXNUM], temp[MAXNUM], final[MAXNUM];
13 
14 double dist(Point a, Point b) {
15     int x = a.x - b.x;
16     int y = a.y - b.y;
17     return sqrt(x*x + y*y);
18 }
19 
20 // feet, temp_feet, level, nodes[], temp[], visit[], final[]
21 void traverse(double& feet, double temp_feet, int level, int num) {
22     if (level == num){
23         feet = temp_feet;
24 
25         for (int i = 0; i < num; i++)
26             final[i] = temp[i];
27     }
28 
29     for (int i = 0; i < num; i++){
30         if (!visit[i]){
31             visit[i] = true;
32             temp[level] = node[i];
33             double next_temp_feet = temp_feet;
34             if (level)
35                 next_temp_feet += dist(temp[level-1], temp[level]);
36 
37             if (feet >= next_temp_feet)
38                 traverse(feet, next_temp_feet, level+1, num);
39             visit[i] = false;
40         }
41     }
42 }
43 
44 int main(int argc, char *argv[]){
45     int num, network_num = 1;
46     cout.setf(ios::fixed);
47     cout.precision(2);
48 
49     while (cin >> num && num){
50         for (int i = 0; i < num; i++)
51             cin >> node[i].x >> node[i].y;
52 
53         double feet = 0.0;
54         for (int i = 0; i < num-1; i++)
55             feet += dist(node[i], node[i+1]);
56 
57         traverse(feet, 0, 0, num);
58         cout << "**********************************************************" << endl;
59 
60         cout << "Network #" << network_num << endl;
61         for (int i = 0; i < num-1; i++){
62             cout << "Cable requirement to connect " << "(";
63             cout << final[i].x << "," << final[i].y << ") to (";
64             cout << final[i+1].x << "," << final[i+1].y << ") is ";
65             cout << dist(final[i], final[i+1]) + 16 << " feet." << endl;
66         }
67         cout << "Number of feet of cable required is " << feet + 16*(num-1) << "." << endl;
68         network_num++;
69     }
70     return 0;
71 }

 

posted @ 2013-02-04 16:48  frankdj  阅读(109)  评论(0)  编辑  收藏  举报