leetcode max-points-on-a-line

/*
 表示很无语，为什么同样的点还要计算在里面，导致一直没有AC
　
*/
/**
 * Definition for a point.
 * struct Point {
 *     int x;
 *     int y;
 *     Point() : x(0), y(0) {}
 *     Point(int a, int b) : x(a), y(b) {}
 * };
 */
class Solution {
public:
    int maxPoints(vector<Point> &points) {
        
        int len = points.size();
        if(len <= 2) return len;
        int ans = 2;
        for(int i = 0 ; i < len ; i ++){
           int du = 0; 
           for(int j = i + 1 ; j < len ; j ++){
                int cnt = 1;
                if(points[j].x == points[i].x && points[j].y == points[i].y){
                     du ++;
                     ans = max(cnt+du , ans);
                     continue;
                }
                cnt ++;
            	for(int k = j + 1 ; k < len ; k ++){
                         
                    	int x = (points[k].x - points[i].x)*(points[k].y - points[j].y);
                    	int y = (points[k].x - points[j].x)*(points[k].y - points[i].y);
                    	if(x == y) cnt ++;
                    
            	}
            	ans = max(cnt+du , ans);
           }
        }
        
        return ans;
    }
};