Max Points on a 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() <= 2) //size is less then or equal to 2 then just return size
return points.size();

unordered_map<string, int> dupMap;
for(int i = 0; i < points.size(); i++){ // delete dubs and keep track of their count in dupMap
string pt = to_string(points[i].x) + ' '+ to_string(points[i].y);
if(dupMap.count(pt) == 0)
dupMap[pt] = 0;
else{
dupMap[pt]++;
points.erase(points.begin() + i--);
}
}

if(points.size() == 1){ //if every item  was a dup
string pt = to_string(points[0].x) + ' '+ to_string(points[0].y);
return dupMap[pt] + 1;
}

int max = 2;
for(int i = 0; i < points.size()-1; i++){//O(N^2) calclate every combination of points
unordered_map<string, int> hashMap;
string pt = to_string(points[i].x) +' '+ to_string(points[i].y);

for(int j = i+1; j < points.size(); j++){
string pt2 = to_string(points[j].x) +' '+ to_string(points[j].y);
string eq = "";
if(points[i].x == points[j].x)
eq = "x = " + to_string(points[i].x); //infinte slope
else{
float m = (float)(points[j].y - points[i].y) / (float)(points[j].x - points[i].x);//slope
m = (m < 0.0005 && m > -0.0005)? 0: m; //rounding to 0 for floats
float b = (float)points[i].y - (float)(m * points[i].x);
eq = "y =" + to_string(m) + '+' + to_string(b); //form equation string
}

if(hashMap.count(eq) == 0){ //havent seen this eq before
hashMap[eq] = 2;
if(dupMap[pt] > 0) //pt has dupes
hashMap[eq] += dupMap[pt];
if(dupMap[pt2] > 0)//pt2 has dupes
hashMap[eq] += dupMap[pt2];
}
else
hashMap[eq] += (dupMap[pt2] > 0)? dupMap[pt2] + 1 : 1;
max = (hashMap[eq] > max)? hashMap[eq] : max;
}
}
return max; //return the max count
}
};