4-Median-Of-Two-Sorted-Arrays.js

/**
 * @param {number[]} nums1
 * @param {number[]} nums2
 * @return {number}
 */
var findMedianSortedArrays = function (nums1, nums2) {
    let [A, B] = [nums1, nums2];
    const total = nums1.length + nums2.length;
    const half = Math.floor(total / 2);

    if (B.length < A.length) {
        [A, B] = [B, A];
    }

    let [l, r] = [0, A.length - 1];
    while (true) {
        const i = l + r;
        const j = half - i - 2;

        const Aleft = i >= 0 ? A[i] : -Infinity;
        const Aright = i + 1 < A.length ? A[i + 1] : Infinity;
        const Bleft = j >= 0 ? B[j] : -Infinity;
        const Bright = j + 1 < B.length ? B[j + 1] : Infinity;

        if (Aleft <= Bright && Bleft <= Aright) {
            if (total % 2) {
                return Math.min(Aright, Bright);
            }

            return (Math.max(Aleft, Bleft) + Math.min(Aright, Bright)) / 2;
        } else if (Aleft > Bright) r = i - 1;
        else l = i + 1;
    }
};