# 2013. Detect Squares
###### tags: `Leetcode` `Medium`
Link: https://leetcode.com/problems/detect-squares/
## Code

class DetectSquares {
    Map<String, Integer> map;
    List<int[]> list;
    public DetectSquares() {
        list = new ArrayList<>();
        map = new HashMap<>();
    }
    
    public void add(int[] point) {
        list.add(point);
        String str = point[0]+"#"+point[1];
        map.put(str, map.getOrDefault(str, 0)+1);
    }
    
    public int count(int[] point) {
        int sum = 0;
        for(int[] p:list){
            if(p[0]==point[0] || p[1]==point[1] || Math.abs(p[1]-point[1])!=Math.abs(p[0]-point[0])) continue;
            sum += (map.getOrDefault(p[0]+"#"+point[1],0)*map.getOrDefault(point[0]+"#"+p[1],0));
        }
        return sum;
    }
}