C++14(g++5.4) 解法, 执行用时: 3ms, 内存消耗: 472K, 提交时间: 2018-08-07 09:59:33

#include<bits/stdc++.h>
using namespace std;
const int maxn=500;
double x[10],y[10];
double dis(int i,int j)
{
    return sqrt((x[i]-x[j])*(x[i]-x[j])+(y[i]-y[j])*(y[i]-y[j]));
}
void solve()
{
    for(int i=0;i<2;i++)
        scanf("%lf%lf",&x[i],&y[i]);
    double ans=fabs(x[0]-x[1])+fabs(y[0]-y[1]);
    double p,q,r;scanf("%lf%lf%lf",&p,&q,&r);
    if(p!=0&&q!=0)
    {
        x[2]=x[0];y[2]=(r-p*x[2])/q;double dis02=fabs(y[2]-y[0]);
        y[3]=y[0];x[3]=(r-q*y[3])/p;double dis03=fabs(x[3]-x[0]);
        x[4]=x[1];y[4]=(r-p*x[4])/q;double dis14=fabs(y[4]-y[1]);
        y[5]=y[1];x[5]=(r-q*y[5])/p;double dis15=fabs(x[5]-x[1]);
        ans=min(ans,dis02+dis14+dis(2,4));
        ans=min(ans,dis02+dis15+dis(2,5));
        ans=min(ans,dis03+dis14+dis(3,4));
        ans=min(ans,dis03+dis15+dis(3,5));
    }
    printf("%.3f\n",ans);
}
int main()
{
    int T;scanf("%d",&T);
    while(T--)solve();
    return 0;
}

C++11(clang++ 3.9) 解法, 执行用时: 3ms, 内存消耗: 460K, 提交时间: 2018-10-01 14:48:09

#include<cstdio>
#include<algorithm>
#include<cmath>
using namespace std;
typedef long long ll;
int T;
double x[6],y[6],p,q,r;
double dis(int i,int j)
{
	return sqrt(1.0*(x[i]-x[j])*(x[i]-x[j])+1.0*(y[i]-y[j])*(y[i]-y[j]));
}
int main()
{
	scanf("%d",&T);
	while(T--)
	{
		scanf("%lf%lf%lf%lf%lf%lf%lf",&x[0],&y[0],&x[1],&y[1],&p,&q,&r);
		double ans=fabs(x[0]-x[1])+fabs(y[0]-y[1]);
		if(p!=0&&q!=0)
		{
			x[2]=x[0],y[2]=(r-p*x[0])/q;
			x[3]=(r-q*y[0])/p,y[3]=y[0];
			x[4]=x[1],y[4]=(r-p*x[1])/q;
			x[5]=(r-q*y[1])/p,y[5]=y[1];
			for(int i=2;i<=3;i++)
				for(int j=4;j<=5;j++)
					ans=min(ans,dis(0,i)+dis(i,j)+dis(j,1));
		}
		printf("%.3f\n",ans); 
	}
	return 0;
}