SESO27 - Editorial

editorial
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Problem Link

To efficiently merge two sorted arrays, we can use a two-pointer technique. This method leverages the fact that both input arrays are already sorted, allowing us to merge them in linear time.

  1. Initialization:

    • We start by initializing two pointers, i and j, to zero. These pointers will be used to traverse the first and second arrays, respectively.
    • We also initialize an empty list (or array) mergedArray to store the result of the merge.

  2. Merging Process:

    • The main idea is to compare the elements pointed to by i and j in the two arrays. The smaller of the two elements is added to the mergedArray, and the corresponding pointer (i or j) is incremented.
    • This process continues until one of the pointers reaches the end of its array, meaning all elements in that array have been processed.

  3. Appending Remaining Elements:

    • After one array is fully traversed, the remaining elements in the other array (if any) are directly appended to the mergedArray. This is because the remaining elements are already sorted and larger than all elements in the mergedArray.

  4. Output:

    • The resulting mergedArray contains all the elements from both input arrays in sorted order. This array is then returned or printed as the output.

Complexity Analysis

  • Time Complexity: The time complexity of this approach is O(n + m), where n and m are the lengths of the two arrays. This is optimal because each element from both arrays is processed exactly once.

  • Space Complexity: The space complexity is O(n + m), which is the space required to store the merged array. The space complexity does not include the space used by the input arrays as they are provided.