# 1313. Decompress Run-Length Encoded List
# 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 [a, b] = [nums[2*i], nums[2*i+1]] (with i >= 0).
# For each such pair, there are a elements with value b in 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] + [4,4,4,4] is [2,4,4,4].


def decompressRLElist(nums):

    a = []

    for i in range(len(nums)):
        if i % 2 == 0:
            b = nums[i]
            while b>0:
                a.append(nums[i + 1])
                b -= 1
    return a

print(decompressRLElist([1,2,3,4]))
