Given n points in the plane that are all pairwise distinct, a "boomerang" is a tuple of points (i, j, k) such that the distance between i and j equals the distance between i and k (the order of the tuple matters).

Find the number of boomerangs. You may assume that n will be at most 500 and coordinates of points are all in the range [-10000, 10000] (inclusive).

Example:

class Solution {public:    int numberOfBoomerangs(vector
     
      
        >& points)     {        if(points.size()<3)            return 0;        int ret=0;        for(int i=0;i
       
        hashmap;            for(int j=0;j
        
         second>=2)                    ret += it->second*(it->second-1);            }        }        return ret;    }    int distance(pair
         
           &a,pair
          
            &b) { int x=(a.first-b.first)*(a.first-b.first); int y=(a.second-b.second)*(a.second-b.second); return x+y; }};
          
         
        
       
      
     

 

Input:[[0,0],[1,0],[2,0]]Output:2Explanation:The two boomerangs are [[1,0],[0,0],[2,0]] and [[1,0],[2,0],[0,0]]