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What difficulty level is this coding question?

This is a medium difficulty Coding & Algorithms question, commonly asked during Technical Screen rounds at Apple.

What role is this question designed for?

This question is commonly asked for Software Engineer candidates at Apple during technical interviews.

Zero out duplicates and sort an array

Quick Overview

This question evaluates proficiency in array manipulation, duplicate handling, and custom sorting logic with attention to time and space complexity, and it falls within the Coding & Algorithms domain.

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Solution

def solution(arr):
    if isinstance(arr, tuple) and len(arr) == 1 and isinstance(arr[0], list):
        arr = arr[0]

    seen = set()
    transformed = []

    for value in arr:
        if value in seen:
            transformed.append(0)
        else:
            seen.add(value)
            transformed.append(value)

    temp = [0] * len(transformed)

    def merge_sort(left, right):
        if right - left <= 1:
            return

        mid = (left + right) // 2
        merge_sort(left, mid)
        merge_sort(mid, right)

        i = left
        j = mid
        k = left

        while i < mid and j < right:
            if transformed[i] <= transformed[j]:
                temp[k] = transformed[i]
                i += 1
            else:
                temp[k] = transformed[j]
                j += 1
            k += 1

        while i < mid:
            temp[k] = transformed[i]
            i += 1
            k += 1

        while j < right:
            temp[k] = transformed[j]
            j += 1
            k += 1

        for idx in range(left, right):
            transformed[idx] = temp[idx]

    merge_sort(0, len(transformed))
    return transformed

Time complexity: O(n log n). Space complexity: O(n).

Quick Overview

Zero out duplicates and sort an array

Constraints

Examples

Solution

Hints