88 Merge Sorted Arrays

November 12, 2024

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

Solution 1

Trick here is to traverse arrays from the end and not from the beginning. Since the maximum number of both arrays will be the last, you can put it to the last element.

Code C#

public class Solution {
    public void Merge(int[] nums1, int m, int[] nums2, int n) {
        var p1 = m - 1;
        var p1Insert = m + n - 1; 
        var p2 = n - 1;

        while(p2 >= 0)
        {
            if (p1 >= 0 && nums1[p1] > nums2[p2])
            {
                nums1[p1Insert] = nums1[p1];
                p1Insert--;
                p1--;
            }
            else
            {
                nums1[p1Insert] = nums2[p2];
                p1Insert--;
                p2--;
            }
        }
    }
}

Complexity

Time O(m + n)
Space O(1)