leetcode 149. Max Points on a Line

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.

  1、遍历每一个点，作为基准点
  2、其他点与之比较，用map来存斜率，特殊考虑 垂直和复制的情况。 

现在有一个数据过不了，网上很多其他人代码也过不了。

/** * 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)            return points.size();               int ret = 2;        for(int i = 0; i < points.size(); i++)        {            int dup = 0;            int ver = 0;            int curcount = 1;            map<long double,int> xielv;                       for(int j=0;j<points.size();j++)            {                if(i != j)                {                    double _x = points[i].x - points[j].x;                    double _y = points[i].y - points[j].y;                                       if(_x == 0 && _y == 0)//两个点相同                        dup++;                    else if(_x == 0)//垂直情况                    {                        if(ver == 0)                            ver = 2;                        else                            ver++;                        curcount = max(curcount, ver);                     }                    else//斜率存在的情况                    {                        long double xie = _y / _x;                        if(xielv[xie] == 0)                            xielv[xie] = 2;                        else                            xielv[xie]++;                        curcount = max(curcount, xielv[xie]);                    }                }            }            ret = max(ret, curcount + dup);       }       return ret;      }};