Decompress Run-Length Encoded List Lab

Easy
4
58.8% Acceptance

In this lab, you will be implementing a function to decompress a Run-Length Encoded list of integers. Run-Length Encoding is a simple form of compression in which runs of data (consecutive occurrences of the same data value) are stored as a single data value and a count. You will be given a list nums of integers representing a list compressed with run-length encoding.

Your task is to consider each adjacent pair of elements [freq, val] = [nums[2*i], nums[2*i+1]] (with i >= 0). For each such pair, there are freq elements with value val concatenated in a sublist. You have to concatenate all the sublists from left to right to generate the decompressed list and return it.

Example

Example 1:

Input: nums = [1,2,3,4] Output: [2,4,4,4] Explanation: The first pair [1,2] means we have freq = 1 and val = 2 so we generate the array [2]. The second pair [3,4] means we have freq = 3 and val = 4 so we generate [4,4,4]. At the end the concatenation [2] + [4,4,4] is [2,4,4,4].

Example 2:

Input: nums = [1,1,2,3] Output: [1,3,3]

Challenges

  1. Export your function decompressRLElist() from 'index.js'.
  2. Write test cases for your function.

Constraints:

  • 2 <= nums.length <= 100
  • nums.length % 2 == 0
  • 1 <= nums[i] <= 100