solution.js

/**
 * @param {number[][]} points
 * @return {number}
 */
var minAreaRect = function (points) {
    // 按y坐标聚合
    const map = {};
    for (let i = 0; i < points.length; i++) {
        const [
            x, y, ] = points[i];
        if (map[y] === undefined) {
            map[y] = {
                [x]: true,
            };
        } else {
            map[y][x] = true;
        }
    }

    let minArea = Infinity;
    const ys = Object.keys(map);
    for (let i = 0; i < ys.length - 1; i++) {
        const xs1Map = map[ys[i]];
        const xs1 = Object.keys(xs1Map);
        if (xs1.length === 1) {
            continue;
        }
        for (let j = i + 1; j < ys.length; j++) {
            const xs2Map = map[ys[j]];
            const xs2 = Object.keys(xs2Map);
            if (xs2.length === 1) {
                continue;
            }
            const deltaY = Math.abs(ys[j] - ys[i]);
            // 给定两个y坐标，找到x坐标一致的
            const candidates = [];
            for (let k = 0; k < xs1.length; k++) {
                if (xs2Map[xs1[k]]) {
                    candidates.push(xs1[k]);
                }
            }
            if (candidates.length < 2) {
                continue;
            }
            candidates.sort((a, b) => a - b);
            // 找到x坐标差值最小的
            const deltaXs = [];
            for (let m = 1; m < candidates.length; m++) {
                deltaXs.push(candidates[m] - candidates[m - 1]);
            }
            const curMinArea = deltaY * Math.min(...deltaXs);
            if (curMinArea < minArea) {
                minArea = curMinArea;
            }
        }
    }

    return minArea === Infinity ? 0 : minArea;
};