CodeForces 671A Recycling Bottles

#pragma comment(linker, "/STACK:1024000000,1024000000")
#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
#include<vector>
#include<map>
#include<set>
#include<queue>
#include<stack>
#include<iostream>
using namespace std;
typedef long long LL;
const double pi=acos(-1.0),eps=1e-6;
void File()
{
    freopen("D:\\in.txt","r",stdin);
    freopen("D:\\out.txt","w",stdout);
}
template <class T>
inline void read(T &x)
{
    char c=getchar(); x=0;
    while(!isdigit(c)) c=getchar();
    while(isdigit(c)) {x=x*10+c-‘0‘; c=getchar();}
}

const int maxn=100010;
double ax,ay,bx,by,tx,ty;
struct X{ double x,y;int id; }s[maxn];
int n;

bool cmp1(X a,X b)
{
    return sqrt((a.x-ax)*(a.x-ax)+(a.y-ay)*(a.y-ay))-sqrt((a.x-tx)*(a.x-tx)+(a.y-ty)*(a.y-ty))
            <
            sqrt((b.x-ax)*(b.x-ax)+(b.y-ay)*(b.y-ay))-sqrt((b.x-tx)*(b.x-tx)+(b.y-ty)*(b.y-ty));
}

bool cmp2(X a,X b)
{
    return sqrt((a.x-bx)*(a.x-bx)+(a.y-by)*(a.y-by))-sqrt((a.x-tx)*(a.x-tx)+(a.y-ty)*(a.y-ty))
            <
            sqrt((b.x-bx)*(b.x-bx)+(b.y-by)*(b.y-by))-sqrt((b.x-tx)*(b.x-tx)+(b.y-ty)*(b.y-ty));
}

bool cmp3(X a,X b)
{
    return a.id<b.id;
}

int a[maxn],sz;

int main()
{
    scanf("%lf%lf%lf%lf%lf%lf",&ax,&ay,&bx,&by,&tx,&ty);

    scanf("%d",&n);
    for(int i=1;i<=n;i++) scanf("%lf%lf",&s[i].x,&s[i].y),s[i].id=i;

    if(n==1)
    {
        double ans;
        ans=min(sqrt((ax-s[1].x)*(ax-s[1].x)+(ay-s[1].y)*(ay-s[1].y))+
                sqrt((tx-s[1].x)*(tx-s[1].x)+(ty-s[1].y)*(ty-s[1].y))
                ,
                sqrt((bx-s[1].x)*(bx-s[1].x)+(by-s[1].y)*(by-s[1].y))+
                sqrt((tx-s[1].x)*(tx-s[1].x)+(ty-s[1].y)*(ty-s[1].y))
                );
        printf("%.6lf\n",ans);
        return 0;
    }

    double ans=999999999999999999;
    double g=0;
    for(int i=1;i<=n;i++) g=g+2*sqrt((s[i].x-tx)*(s[i].x-tx)+(s[i].y-ty)*(s[i].y-ty));

    sort(s+1,s+1+n,cmp1);
    ans=min(ans,
            g+sqrt((s[1].x-ax)*(s[1].x-ax)+(s[1].y-ay)*(s[1].y-ay))
            -sqrt((s[1].x-tx)*(s[1].x-tx)+(s[1].y-ty)*(s[1].y-ty)));
    for(int i=1;i<=min(n,2);i++) a[sz++]=s[i].id;

    sort(s+1,s+1+n,cmp2);
    ans=min(ans,
            g+sqrt((s[1].x-bx)*(s[1].x-bx)+(s[1].y-by)*(s[1].y-by))
            -sqrt((s[1].x-tx)*(s[1].x-tx)+(s[1].y-ty)*(s[1].y-ty)));
    for(int i=1;i<=min(n,2);i++) a[sz++]=s[i].id;

    sort(s+1,s+1+n,cmp3);

    for(int i=0; i<sz; i++)
    {
        for(int j=0; j<sz; j++)
        {
            if(a[j]==a[i]) continue;

            double tmp=g;
            tmp=tmp+sqrt((s[a[i]].x-ax)*(s[a[i]].x-ax)+(s[a[i]].y-ay)*(s[a[i]].y-ay));
            tmp=tmp+sqrt((s[a[j]].x-bx)*(s[a[j]].x-bx)+(s[a[j]].y-by)*(s[a[j]].y-by));
            tmp=tmp-sqrt((s[a[i]].x-tx)*(s[a[i]].x-tx)+(s[a[i]].y-ty)*(s[a[i]].y-ty));
            tmp=tmp-sqrt((s[a[j]].x-tx)*(s[a[j]].x-tx)+(s[a[j]].y-ty)*(s[a[j]].y-ty));

            ans=min(ans,tmp);
        }
    }
    printf("%.6lf\n",ans);
    return 0;
}