Merge Sorted Array

Question: Given two sorted integer arrays nums1 and nums2, merge nums2 into nums1 as one sorted array.

Note:

• The number of elements initialized in nums1 and nums2 are m and n respectively.
• You may assume that nums1 has enough space (size that is greater or equal to m + n) to hold additional elements from nums2.

Example:

Input:
nums1 = [1,2,3,0,0,0], m = 3
nums2 = [2,5,6],       n = 3
Output: [1,2,2,3,5,6]

You may view the full question here.

Approach 1: Let’s try in-place sorting —

//Approach 1
//Runtime: 0ms
//Memory usage: 37.3MB
class Solution {
    public void merge(int[] nums1, int m, int[] nums2, int n) {
        m--;
        n--;
        for(int i = nums1.length-1; i>=0; i--){
            
            if(m>=0 && n>=0){
                if(nums1[m]>nums2[n]){
                    nums1[i] = nums1[m];
                    m--;
                } else {
                    nums1[i] = nums2[n];
                    n--;
                }
            } else if(m>=0){
                nums1[i] = nums1[m];
                m--;
            } else {
                nums1[i] = nums2[n];
                n--;
            }
        }
    }
}

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Cheers & Chao!