Apply Operations To An Array · Interview Problem

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Leetcode

Medium

Arrays

Simulation

Apply Operations To An Array

Apply a set of simple transformation rules to an array, then compact the result by moving zeros to the end.

Acceptance 0%

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Problem Statement

Problem

You are given an integer array nums. Perform the following operation on the array from left to right:

If nums[i] == nums[i + 1], replace nums[i] with 2 * nums[i] and replace nums[i + 1] with 0.
Otherwise, leave the pair unchanged.

After processing all adjacent pairs once, shift all zeros to the end of the array while preserving the relative order of the non-zero elements.

Return the transformed array.

Notes

Each adjacent pair is considered once from left to right.
When a value is doubled, the next element in that pair becomes 0.
The final zero-shifting step is part of the required output.

Input Format

An integer array nums of length n.

The array is processed in-place conceptually, but return the final transformed array.

Output Format

Return an integer array representing the result after applying the adjacent-pair transformation and then moving all zeros to the end.

Constraints

1 <= n
Elements are integers.
Exact official constraints are not provided in the source metadata; assume standard interview-scale array sizes.

Examples

Sample cases returned by the problem API.

Example 1

Input

nums = [1,2,2,1,1,0]

Output

[1,4,2,0,0,0]

Explanation

2 and 2 become 4 and 0.
1 and 1 become 2 and 0.
After moving all zeros to the end, the array becomes [1,4,2,0,0,0].

Example 2

Input

nums = [0,0,3,3]

Output

[6,0,0,0]

Explanation

0 and 0 are equal, so the first becomes 0 and the second becomes 0.
3 and 3 become 6 and 0.
After compacting non-zero values, the result is [6,0,0,0].

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