uva 216 Getting in Line

直接用next_permutation函数排列，再进行暴力循环就好了。

#include "stdio.h"
#include "math.h"
#include<algorithm>
using namespace std;


int b[10],x[10],y[10],n,a[10];
double sum,temp,minx;


double len(int x1,int y1,int x2,int y2)
{
    double t;
    t=(x1-x2)*(x1-x2)+(y1-y2)*(y1-y2);
    return sqrt(t)+16;
}


void fun()
{
    int i;
    sum=0;
    for(i=0;i<n-1;i++) sum+=len(x[b[i]],y[b[i]],x[b[i+1]],y[b[i+1]]);
    if(sum<minx){
        minx=sum;
        for(i=0;i<n;i++)
            a[i]=b[i];
    }
}


int main()
{
    int i,cas=0;
    while(~scanf("%d",&n))
    {
        if(n==0) break;
        for(i=0;i<n;i++)
        {
            scanf("%d%d",&x[i],&y[i]);
            b[i]=i;
        }
        minx=99999999;
        do{fun();}while(next_permutation(b,b+n));
        printf("**********************************************************
");
        printf("Network #%d
",++cas);
        for(i=0;i<n-1;i++)

printf("Cable requirement to connect (%d,%d) to (%d,%d) is %.2f feet.
",x[a[i]],y[a[i]],x[a[i+1]],y[a[i+1]],len(x[a[i]],y[a[i]],x[a[i+1]],y[a[i+1]]));
        printf("Number of feet of cable required is %.2f.
",minx);
    }
    return 0;
}