Merge Two Sorted Arrays

Problem

Given two sorted arrays arr1 and arr2, return a single sorted array in non-decreasing order.

Examples:

mergeSortedArrays([1,2,3], [2,5,6]);
// [1,2,2,3,5,6]

mergeSortedArrays([1], []);
// [1]

Time Complexity

The algorithm should have a time complexity of O(n1 + n2) where n1 and n2 are the sizes of arr1 and arr2 respectively.