## Description

https://leetcode.com/problems/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`

## Explanation

Step by 2 each time to add pairs.

## Python Solution

```
class Solution:
def decompressRLElist(self, nums: List[int]) -> List[int]:
results = []
for i in range(1, len(nums), 2):
freq = nums[i - 1]
value = nums[i]
for j in range(freq):
results.append(value)
return results
```

- Time Complexity: O(logN)
- Space Complexity: O(N)