求直线被确定的最大次数

问题描述：
Given
n points on a 2D plane, find the maximum number of points that lie on the same straight line.
在一个给定的n个点的平面，求在相同的直线最多的点的点数。
 
 
 
 
 
class Solution {
public:
    int maxPoints(vector<Point> &points){
        //k存在
        map<double,int> k0[points.size()];
        //k不存在
        int k1[points.size()] = {0};
        int k_maxnum = 0;
        vector<Point>::iterator it1 = points.begin();
        vector<Point>::iterator it_end = points.end();
        int position = 0;
        for(; it1 != it_end; it1++)
            {
            Point p1(it1->x,it1->y);
            for(vector<Point>::iterator it2 = points.begin();it2 != it_end;it2++)
                {
                //同个点
                if(it2 == it1)
                    {
                    continue;
                }
                //斜率不存在
                else if(it2->x == it1->x)
                    {
                    k1[position] += 1;
                }
                //斜率存在
                else
                    {
                    Point p2(it2->x,it2->y);
                    double k = (p2.y - p1.y)/(p2.x - p1.x);
                    map<double,int>::iterator it3 = (k0+position).find(k);
          
if( it = map.end() )
                    
{
                        (k0+position)[k] = 1;
                    )
                    else{
                        (k0+position)[k] = (k0+position)[k]+1;
                    }
                }   
            }
            position++;

        }
            
        for(int i1 = 0; i1<points.size();i1++)
            {
            for(map<double,int>::iterator it4 = k0[i1].begin(); it4 != k0[i1].end();it4++)
                {
                if(it4->second > k_maxnum)k_maxnum = it4->second;
            }
        }
            //int k1[points.size()] = {0};
        for(int i2 = 0; i2<points.size(); i2++)
            {
            if(k1[i2] > k_maxnum)k_maxnum = k1[i2];
        }
            
        return k_maxnum;
    }
        
        
        
        
        
};
 
2.
class Solution {
public:
    int maxPoints(vector<Point> &points) {
        int size = points.size();
        if(size == 0)
            return 0;
        else if(size == 1)
            return 1;
             
        int ret = 0;
        for(int i = 0;i<size;i++){
             
            int curmax = 1;
            map<double,int>mp;
            int vcnt = 0; //垂直点
            int dup = 0; //重复点
            for(int j = 0;j<size;j++){
                 
                if(j!=i){
                    double x1 = points[i].x - points[j].x;
                    double y1 = points[i].y - points[j].y;
                    if(x1 == 0 && y1 == 0){   //重复
                        dup++;
                    }else if(x1 == 0){      //垂直
                        if(vcnt == 0)
                            vcnt = 2;
                        else
                            vcnt++;
                        curmax = max(vcnt,curmax);
                    }else{

                        double k = y1/x1;          //斜率
                        if(mp[k] == 0)
                            mp[k] = 2;
                        else
                            mp[k]++;
                        curmax = max(mp[k],curmax);
                    }                   

                }
            }
            ret = max(ret,curmax+dup);           

        }
        return ret;
         
    }
};