# Leetcode - Decompress Run-Length Encoded List Solution

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`

## Solution in Python

```
class Solution:
def decompressRLElist(self, nums: List[int]) -> List[int]:
output = []
for i in range(0,len(nums)-1,2):
output.extend([nums[i+1]]*nums[i])
return output
```