DAY 56 OF 90 · Loops inside loops

Star staircase

Medium90 Days of Looping

Inputs

n is a whole number from 0 to 10.

Your tasks

Create an empty list rows.
Use an outer loop for each row number r from 1 up to and including n. Build a text line with an inner loop that adds one "*" for each of the r positions.
Add line to rows.
Complete staircase so it returns rows. Return it, do not print it.

Example

With n = 4, staircase returns ["*", "**", "***", "****"].

Rules

Row 1 has one star, row 2 has two, and so on.
If n is 0, return an empty list.

Test data

TEST DATA 1: n is 4

TEST DATA 2: n is 0

Practice focus

Nested loops compare every pair and build rows. The slow, simple answer to most problems is two loops. Knowing it is what lets you see how to beat it.

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