0004-median-of-two-sorted-arrays.ts

function findMedianSortedArrays(nums1: number[], nums2: number[]): number {
    if (nums2.length < nums1.length) {
        [nums1, nums2] = [nums2, nums1];
    }

    let [left, right] = [0, nums1.length - 1];
    const totalLength = nums1.length + nums2.length;
    const mid = totalLength >> 1;
    const isEven = totalLength % 2 === 0;

    while (true) {
        const mid1 = left + right;
        const mid2 = mid - mid1 - 2;

        const getLeft = (nums, index) => (0 <= index ? nums[index] : -Infinity);
        const getRight = (nums, index) =>
            index + 1 < nums.length ? nums[index + 1] : Infinity;
        const [aLeft, bLeft] = [getLeft(nums1, mid1), getLeft(nums2, mid2)];
        const [aRight, bRight] = [getRight(nums1, mid1), getRight(nums2, mid2)];

        if (aLeft <= bRight && bLeft <= aRight) {
            return isEven
                ? (Math.max(aLeft, bLeft) + Math.min(aRight, bRight)) / 2
                : Math.min(aRight, bRight);
        }

        if (aLeft <= bRight) {
            left = mid1 + 1;
        }

        if (bRight < aLeft) {
            right = mid1 - 1;
        }
    }
}