HDU 4463 Outlets


タイトルリンク:Outlets
問題:
Outlets
Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 2323    Accepted Submission(s): 1096
Problem Description
In China, foreign brand commodities are often much more expensive than abroad. The main reason is that we Chinese people tend to think foreign things are better and we are willing to pay much for them. The typical example is, on the United Airline flight, they give you Haagendazs ice cream for free, but in China, you will pay $10 to buy just a little cup.
So when we Chinese go abroad, one of our most favorite activities is shopping in outlets. Some people buy tens of famous brand shoes and bags one time. In Las Vegas, the existing outlets can't match the demand of Chinese. So they want to build a new outlets in the desert. The new outlets consists of many stores. All stores are connected by roads. They want to minimize the total road length. The owner of the outlets just hired a data mining expert, and the expert told him that Nike store and Apple store must be directly connected by a road. Now please help him figure out how to minimize the total road length under this condition. A store can be considered as a point and a road is a line segment connecting two stores.
 
Input
There are several test cases. For each test case: The first line is an integer N( 3 <= N <= 50) , meaning there are N stores in the outlets. These N stores are numbered from 1 to N. The second line contains two integers p and q, indicating that the No. p store is a Nike store and the No. q store is an Apple store. Then N lines follow. The i-th line describes the position of the i-th store. The store position is represented by two integers x,y( -100<= x,y <= 100) , meaning that the coordinate of the store is (x,y). These N stores are all located at different place. The input ends by N = 0.
 
Output
For each test case, print the minimum total road length. The result should be rounded to 2 digits after decimal point.
 
Sample Input

   
   
   
   
4 2 3 0 0 1 0 0 -1 1 -1 0

 
Sample Output

   
   
   
   
3.41

 
Source
2012 Asia Hangzhou Regional Contest
 
タイトル:
いくつかの点を与えて、1本の辺を知っていて、最小の辺とを求めて、すべての点をつなぎます.実は、最小生成木です.事前に任意の2点の间の距离を求めて、データの量は比较的に小さくて、primとkruscalはすべてできて、私は直接暴力でだめです....
コード:
#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <vector>
#include <cmath>
using namespace std;
int road[51][51],x[51],y[51];
bool flag[51];
int dis(int x0,int y0,int x1,int y1)
{
	return (x0-x1)*(x0-x1)+(y0-y1)*(y0-y1);
} 
int main()
{
	int n,p,q,tmp,cnt,fm,to;
	double cost;
	while(scanf("%d",&n)&&n)
	{
	   cost=0;
	   cnt=2;
	   vector <int> store;
	   memset(flag,-1,sizeof(flag));
	   scanf("%d%d",&p,&q);
	   for(int i=1;i<=n;i++)
	   {
   	      scanf("%d%d",&x[i],&y[i]);	
   	   }	
   	   for(int i=1;i<n;i++)
	   {
   	     for(int j=i+1;j<=n;j++)
		 {
 			tmp=dis(x[i],y[i],x[j],y[j]);
 			road[i][j]=road[j][i]=tmp;
	     }	
   	   } 
   	   store.push_back(p);
   	   store.push_back(q);
   	   flag[p]=flag[q]=0;
   	   cost+=sqrt(1.0*road[p][q]);
   	   while(cnt<n)
   	   {
   	   	 tmp=99999999;
   	   	 for(int i=0;i<store.size();i++)
   	   	 {
 	   	     for(int j=1;j<=n;j++)
			 {
			 	if(flag[j])
			 	{
 				  if(road[store[i]][j]<tmp)
 				  {
				    tmp=road[store[i]][j];
				    fm=store[i];
				    to=j; 	
			      }
			 	}
 			 }	
   	     }
   	     cnt++;
   	     flag[to]=0;
   	     cost+=sqrt(1.0*road[fm][to]);
   	     store.push_back(to);
   	   }
   	   printf("%.2lf
",cost); } return 0; }