You are given two integer arrays nums1 and nums2, sorted in non-decreasing order, and two integers m and n, representing the number of elements in nums1 and nums2 respectively.

Merge nums1 and nums2 into a single array sorted in non-decreasing order.

The final sorted array should not be returned by the function, but instead be stored inside the array nums1. To accommodate this, nums1 has a length of m + n, where the first m elements denote the elements that should be merged, and the last n elements are set to 0 and should be ignored. nums2 has a length of n.

Input: nums1 = [1,2,3,0,0,0], m = 3, nums2 = [2,5,6], n = 3 Output: [1,2,2,3,5,6] Explanation: The arrays we are merging are [1,2,3] and [2,5,6]. The result of the merge is [1,2,2,3,5,6] with the underlined elements coming from nums1.

var merge = function(nums1, m, nums2, n) {
    let nums1Index = 0;
    let nums2Index = 0;
    for (let i = 0 ; i < nums1.length ; i++) {
        if (nums2Index === n) {
            nums1Index++;
        } else if (nums1Index === m) {
            nums1[i] = nums2[nums2Index]
            nums2Index++;
        } else if (nums1[i] <= nums2[nums2Index]) {
            nums1Index++;
        } else if (nums1[i] > nums2[nums2Index]) {
            // shift
            for (let k = nums1.length - 1 ; k > i ; k--){
                nums1[k] = nums1[k-1]
            }
            nums1[i] = nums2[nums2Index];
            nums2Index++;
        }
    }
};