【算法】shortest distance

好不容易找到的。

#include<iostream>
#include<iomanip>
#include<cmath>
using namespace std;
double a,b,c,x,y,z,ans,l,w,h;
double f(double x)
{
    return (double(x*x));
}

double min(double x,double y)
{
    if(x>y)  return y;
    else return x;
}

void count1()
{
    ans=sqrt(double(f(a-x)+f(b-y)+f(c-z)));
}

void count2()
{
    double ans1,ans2;
    if(b==0||b==w)
    {
        ans1=sqrt(double(min(f(h-z+w+h-c),f(z+w+c))+f(x-a)));
        ans2=sqrt(double(min(f(l-x+w+l-a),f(x+w+a))+f(c-z)));
    }
    else if(a==0||a==l)
    {
        ans1=sqrt(double(min(f(w-y+l+w-b),f(y+l+b))+f(c-z)));
        ans2=sqrt(double(min(f(h-z+l+h-c),f(z+l+c))+f(b-y)));
    }
    else
    {
        ans1=sqrt(double(min(f(w-y+h+w-b),f(y+h+b))+f(x-a)));
        ans2=sqrt(double(min(f(l-x+h+l-a),f(x+h+a))+f(b-y)));
    }
    ans=min(ans1,ans2);
}

void count3()
{
    if(a==0||a==l)
    {
        if(y==0||y==w)
            ans=sqrt(double(f(labs(x-a)+labs(b-y))+f(c-z)));
        else
            ans=sqrt(double(f(labs(z-c)+labs(x-a))+f(b-y)));
    }
    else if(b==0||b==w)
    {
        if(x==0||x==l)
            ans=sqrt(double(f(labs(x-a)+labs(b-y))+f(c-z)));
        else
            ans=sqrt(double(f(labs(c-z)+labs(b-y))+f(a-x)));
    }
    else
    {
        if(x==0||x==l)
            ans=sqrt(double(f(labs(c-z)+labs(x-a))+f(b-y)));
        else
            ans=sqrt(double(f(labs(c-z)+labs(b-y))+f(a-x)));
    }
}

int main()
{
      cin>>l>>w>>h;
      cin>>a>>b>>c>>x>>y>>z;
      if((a==x&&(a==0||a==l))||(b==y&&(b==0||b==w))||(c==z&&(c==0||c==h)))
          count1();
      else if((a==0&&x==l)||(b==0&&y==w)||(c==0&&z==h)||(a==l&&x==0)||(b==w&&y==0)||(c==h&&z==0))
          count2();
      else
          count3();
      cout<<setiosflags(ios::fixed)<<setprecision(2)<<ans<<endl;
return 0;
}