poj 2253 最短路

2015/1/27

最短路转下思路 或者  二分

POJ去提交，别忘记浮点数G++用 %f..

#include<map>
#include<queue>
#include<stack>
#include<cmath>
#include<vector>
#include<climits>
#include<stdio.h>
#include<string.h>
#include<iostream>
#include<algorithm>
#include<iomanip>
using namespace std;
typedef long long ll;  

#define mod 10007
#define lson pos<<1,l,mid
#define sc(n) scanf("%d",&n)
#define rson pos<<1|1,mid+1,r
#define pr(n) printf("%d\n",n)
#define met(n,m) memset(n, m, sizeof(n))
#define F(x,y,i) for(int i = x;i > y; i--)
#define f(x,y,i) for(int i = x;i < y; i++)
#define ff(x,y,i) for(int i = x;i <= y; i++)
#define FF(x,y,i) for(int i = x;i >= y; i--) 

const int N=100500;
const int inf = INT_MAX;

int Max(int a,int b)
{
	return a>b?a:b;
}

int Min(int a,int b)
{
	return  a<b?a:b;
}

struct node{
	int x;
	int y;
}s[1005];

int dis[1005];
int vis[1005];

int leave(int a,int b)
{
	return (s[a].x - s[b].x)*(s[a].x - s[b].x) + (s[a].y - s[b].y)*(s[a].y - s[b].y);
}

int main()  
{  
    int n, m, tot, x, k;
    tot = 1;
    while(~scanf("%d",&n) && n)
    {
    	int temp;
    	met(vis,0);
    	f(0,n,i)
    	{
	    	scanf("%d%d",&s[i].x,&s[i].y);
	    }
	    f(0,n,i)
	    {
    		dis[i] = leave(0,i);
    	}
    	
		vis[0] = 1;
	    
	    f(0,n-1,i)
	    {
    		temp = inf;
    		f(0,n,j)
    		{
		    	if(!vis[j] && dis[j] < temp)
		    	{
	    			temp = dis[j];  
         			k = j;
	    		}
		    }
		    vis[k] = 1;
		    
		    f(0,n,j)
		    {
    			if(!vis[j])
    			{
			    	if(dis[j] > Max(dis[k],leave(k,j)))
			    	{
	    				dis[j] = Max(dis[k],leave(k,j));
	    			}
			    }
    		}
     
    	}
		    cout<<"Scenario #"<<tot++<<endl;  
		    printf("Frog Distance = %.3lf\n\n",sqrt(1.0*dis[1])); 
    
				
    }
    return 0;  
}