Given n points on a 2D plane, find the maximum number of points that lie on the same straight line.
class Solution {
public:
int maxPoints(vector<Point>& points) {
unordered_map<float,int> mp;
int maxNum = 0;
for(int i=0;i<points.size();i++)
{
mp.clear();
mp[INT_MAX] = 0; //当只有一个元素时，这个赋值有用
int duplicate = 1;
for(int j=0;j<points.size();j++)
{
if(j==i)
continue;
if(points[i].x == points[j].x&&points[i].y == points[j].y)
{
duplicate++;
continue;
}
float k = points[i].x == points[j].x ? INT_MAX : (float)(points[i].y - points[j].y)/(points[i].x - points[j].x);
mp[k]++;
}
unordered_map<float,int>::iterator it = mp.begin();
for(;it!=mp.end();it++)
{
if(it->second + duplicate > maxNum)
maxNum = it->second + duplicate;
}
}
return maxNum;
}
};
