88. Merge Sorted Array

class Solution {
    public void merge(int[] nums1, int m, int[] nums2, int n) {
        int a = m - 1;
        int b = n - 1;
        int length = a + b - 1; 
        while ((a > 0) && (b > 0)) {
            if (nums1[a] > nums2[b]) {
                nums1[length] = nums1[a];
                a--;
            } else {
                nums1[length] = nums2[b];
                b--;
            }
            length--;
        }
        while (b >= 0) {
            nums1[length] = nums2[b];
            length--;
            b--; 
        }
    }
}