leetcode[149]Max Points on a Line

Given n points on a 2D plane, find the maximum number of points that lie on the same straight line.

/**
 * 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) {
    if(points.size()<3)return points.size();
    int sizeMax=0;
    for(int i=0;i<points.size();i++)
    {
        int repeat=1;
        map<double,int> smap;
        smap.clear();
        for(int j=0;j<points.size();j++)
        {
            if(i==j)continue;
            if(points[i].x==points[j].x&&points[i].y==points[j].y)
            {
                repeat++;
                continue;
            }
            double k=points[i].x==points[j].x?INT_MAX:double(points[j].y-points[i].y)/(points[j].x-points[i].x);
            smap[k]++;
        }
        if(smap.size()==0)
        {
            sizeMax=sizeMax>repeat?sizeMax:repeat;
            continue;
        }
        for(map<double,int>::iterator iter=smap.begin();iter!=smap.end();iter++)
        {
            sizeMax=sizeMax>(iter->second+repeat)?sizeMax:(iter->second+repeat);
        }
    }
    return sizeMax;
}
};