1313. Decompress Run-Length Encoded List LeetCode Solution

In this guide, you will get 1313. Decompress Run-Length Encoded List LeetCode Solution with the best time and space complexity. The solution to Decompress Run-Length Encoded List problem is provided in various programming languages like C++, Java, and Python. This will be helpful for you if you are preparing for placements, hackathons, interviews, or practice purposes. The solutions provided here are very easy to follow and include detailed explanations.

Table of Contents

1. Problem Statement
2. Complexity Analysis
3. Decompress Run-Length Encoded List solution in C++
4. Decompress Run-Length Encoded List solution in Java
5. Decompress Run-Length Encoded List solution in Python
6. Additional Resources

Problem Statement of Decompress Run-Length Encoded List

We are given a list nums of integers representing a list compressed with run-length encoding.
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. Concatenate all the sublists from left to right to generate the decompressed list.
Return the decompressed list.

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]

Constraints:

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

Complexity Analysis

• Time Complexity:
• Space Complexity:

1313. Decompress Run-Length Encoded List LeetCode Solution in C++

class Solution {
 public:
  vector<int> decompressRLElist(vector<int>& nums) {
    vector<int> ans;

    for (int i = 0; i < nums.size(); i += 2)
      ans.insert(ans.end(), nums[i], nums[i + 1]);

    return ans;
  }
};
/* code provided by PROGIEZ */

1313. Decompress Run-Length Encoded List LeetCode Solution in Java

class Solution {
  public int[] decompressRLElist(int[] nums) {
    List<Integer> ans = new ArrayList<>();

    for (int i = 0; i < nums.length; i += 2)
      for (int freq = 0; freq < nums[i]; ++freq)
        ans.add(nums[i + 1]);

    return ans.stream().mapToInt(Integer::intValue).toArray();
  }
}
// code provided by PROGIEZ

1313. Decompress Run-Length Encoded List LeetCode Solution in Python

class Solution:
  def decompressRLElist(self, nums: list[int]) -> list[int]:
    ans = []

    for i in range(0, len(nums), 2):
      ans += [nums[i + 1]] * nums[i]

    return ans
 # code by PROGIEZ

Additional Resources

• Explore all LeetCode problem solutions at Progiez here
• Explore all problems on LeetCode website here

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