Unpack Count-Value Pairs

Easy

A warehouse stores long lists in compact form: instead of repeating numbers it writes "count, value" pairs. The array packed is a sequence of such pairs: packed[0] says how many times to repeat packed[1], packed[2] says how many times to repeat packed[3], and so on. Rebuild the original list: expand each pair into that many copies of its value and join the pieces left to right, in the order the pairs appear.

Example 1

packed=[2, 7, 1, 3] → [7, 7, 3]

The pair (2, 7) gives two 7s and the pair (1, 3) gives one 3: [7, 7, 3].

Example 2

packed=[3, 5, 2, 5] → [5, 5, 5, 5, 5]

Neighbouring pairs may share a value: three 5s and then two more, five in total.

Example 3

packed=[1, 100] → [100]

Constraints

2 ≤ len(packed) ≤ 100
len(packed) is even
1 ≤ packed[i] ≤ 100

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Topics

Array

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Input

packed=[2, 7, 1, 3]

Expected

[7, 7, 3]

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