149.直线上最多的点数.js

/*
 * @lc app=leetcode.cn id=149 lang=javascript
 *
 * [149] 直线上最多的点数
 */

// @lc code=start
/**
 * @param {number[][]} points
 * @return {number}
 */
var maxPoints = function(points) {
    if (points.length <2|| points == null) return points.length;
    let max = 2;
    for (let i=0;i<points.length;i++) {
        let [p1x, p1y] = points[i];
        let samePoint = 1, map = {'base':0}; // to avoid when map = {}, the max value is -Infinity
        for (let j=i+1;j<points.length;j++) {
            if (points[i][0] == points[j][0] && points[i][1] == points[j][1]) {
                samePoint++;
            } else {
                let [p2x, p2y] = points[j];
                let slope = 1000000.0 * (p2y - p1y)/(p2x - p1x);
                if (!Number.isFinite(slope)) slope = "v";
                else if (Number.isNaN(slope)) slope = "h";
                map[slope] = map[slope]+1||1;
            }   
        }
        max = Math.max(Math.max(...Object.values(map))+samePoint, max);
    }
    return max;
};
// @lc code=end