In kernel ridge regression we have seen the final solution was not sparse in the variables ® . We will now formulate a regression method that is sparse, i.e. it has the concept of support vectors that determine the solution. The thing to not

Given n points on a 2D plane, find the maximum number of points that lie on the same straight line. 分析：首先要注意的是，输入数组中可能有重复的点。由于两点确定一条直线，一个很直观的解法是计算每两个点形成的直线，然后把相同的直线合并，最后包含点最多的直线上点的个数就是本题的解。我们知道表示一条直线可以用斜率和y截距两个浮点数（垂直于x轴的直线斜率为无穷大，截距用x截距），同时还需要保存每