88. 合并两个有序数组

https://leetcode-cn.com/problems/merge-sorted-array/

func merge(_ nums1: inout [Int], _ m: Int, _ nums2: [Int], _ n: Int) {
    if n <= 0 {return}
    var length1 = m - 1
    var length2 = n - 1
    var count = m + n - 1
    
    while length1 >= 0 && length2 >= 0 {
        if nums1[length1] > nums2[length2] {
            nums1[count] = nums1[length1]
            length1 = length1 - 1
        } else {
            nums1[count] = nums2[length2]
            length2 = length2 - 1
        }
        count = count - 1
    }
    for idx in stride(from: 0, to: length2 + 1, by: 1) {
        nums1[idx] = nums2[idx]
    }
}