牛客OJ21842---正方形检测

#include<bits/stdc++.h>
using namespace std;
int X[4],Y[4],s[10],cnt,flag;
int main()
{
  flag = 1;
  for(int i = 0;i <4;i++){
    cin>>X[i];
  }
  for(int j = 0;j<4;j++){
    cin>>Y[j];
  } 
  for(int i = 0;i < 4;i++){//每次选取两个点   
    for(int j =i+1;j<4;j++){
      s[cnt++] = (X[i]-X[j])*(X[i]-X[j])+(Y[i]-Y[j])*(Y[i]-Y[j]);  
    }
  } 
  sort(s,s+6);
//  cout<<"======================"<<endl;
//  for(int i = 0; i < 6;i++){
//    cout<<s[i]<<"\t";
//  }
//  cout<<endl;
//  cout<<"======================"<<endl;
  if(s[0]==s[1]&&s[1]==s[2]&&s[2]==s[3] && s[4]==s[5]){
    cout<<"It's a square"<<endl;
  }else{
    cout<<"Not a square"<<endl;
  }
  return 0;
 }