Problem 2228. Time Expansion

How can you slow down any discrete-time signal?

Example

Input original signal x.

 x = [1 2 3 -1 -2 -5 -4] 

We want to slow down n=3 times original signal. Output signal must be like y.

 y = [1 0 0 2 0 0 3 0 0 -1 0 0 -2 0 0 -5 0 0 -4]