xtu read problem training B - Tour

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <cmath>
 5 #include <algorithm>
 6 #include <climits>
 7 #include <vector>
 8 #include <queue>
 9 #include <cstdlib>
10 #include <string>
11 #include <set>
12 #define LL long long
13 #define INF 0x3f3f3f3f
14 using namespace std;
15 struct point{
16     int x,y;
17 }p[10010];
18 bool cmp(const point &a,const point &b){
19     return (a.x > b.x || a.x == b.x && a.y > b.y);
20 }
21 double dis(point a,point b){
22     double temp = (a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y);
23     return sqrt(temp);
24 }
25 double ds[1010][1010],dp[1010][1010];
26 int main(){
27     int n,i,j;
28     double ans = 0;
29     while(~scanf("%d",&n)){
30         for(i = 0; i < n; i++)
31             scanf("%d%d",&p[i].x,&p[i].y);
32         sort(p,p+n,cmp);
33         for(i = 1; i <= n; i++){
34             for(j = 1; j <= n; j++){
35                 dp[i][j] = INF;
36                 ds[i][j] = dis(p[i-1],p[j-1]);
37             }
38         }
39         dp[1][1] = 0;
40         for(i = 2; i <= n; i++){
41             for(j = 1; j <= n; j++){
42                 dp[i][j] = min(dp[i][j],dp[i-1][j]+ds[i][i-1]);
43                 dp[i][i-1] = min(dp[i][i-1],dp[i-1][j]+ds[j][i]);
44             }
45         }
46         printf("%.2f\n",dp[n][n-1]+ds[n][n-1]);
47     }
48     return 0;
49 }