解题报告：最多有多少个点在一条直线上

http://www.lintcode.com/zh-cn/problem/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:    /**     * @param points an array of point     * @return an integer     */ int maxPoints(vector<Point>& points) {// Write your code here  int maxc = 0;if (points.size()>2)for (int i = 0; i < points.size() - 2; i++){for (int z = i+1; z < points.size() ; z++){double x, c;  if (points[z].x - points[i].x == 0){//x坐标上的垂直线int ret = 2;for (int j = i + 1; j < points.size(); j++){if (j == z)continue;if (points[j].x == points[i].x){ret++;}}maxc = max(maxc, ret);} else if (points[z].y - points[i].y == 0){//x坐标上的平行线int ret = 2;for (int j = i + 1; j < points.size(); j++){if (j == z)continue;if (points[j].y == points[i].y){ret++;}}maxc = max(maxc, ret);}else{// 1 3 2 6 x = (points[z].y - points[i].y) / (double)(points[z].x - points[i].x);c = points[i].y - points[i].x*x;int ret = 2;for (int j = i + 1; j < points.size(); j++){if (j == z)continue;if (fabs(points[j].x*x + c - points[j].y)<1e-6 ){ret++;}  }maxc = max(maxc, ret);}}}else  {return points.size();} return maxc;}};