Run-Length Decode

Problem

Decode a run-length encoded vector.

pairs is a list of [count, value] pairs; each pair expands to count copies of value. A count of zero contributes nothing.

Return the decoded list.

Hint

Multiply a one-element list by the count and extend the output.

case 1

in: [[[2,"a"],[1,"b"],[3,"a"]]]

expected: ["a","a","b","a","a","a"]

case 2

in: [[]]

expected: []

case 3

in: [[[0,5]]]

expected: []

case 4

in: [[[2,-1],[2,0]]]

expected: [-1,-1,0,0]

Starter codePython

def rle_decode(pairs):
    # Your code here
    pass

4 test cases · run your code against them in the editor