letcode_1313.py

# 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].
# Input: nums = [1,1,2,3]
# Output: [1,3,3]
# nums = [1,2,3,4]
# freq = 0
nums = [1,1,2,3]
output = []
a = 0
for i in range(0, len(nums)-1, 2):
    freq, val = nums[i], nums[i+1]
    cont = 0
    while freq != cont:
        output.append(val)
        cont +=1
    
print(output)