504. What is a Pascal Triangle?

Given a number N, write a program to print the first N lines of the Pascal triangle.

Pascal Triangle:

Note: In Pascal's triangle, each number is the sum of the two numbers directly above it.

(Image reference: Wiki)

Approach:

Initialize list row and list of lists as all_rows.
We will keep updating the list row by adding more numbers and after each iteration, create a copy of the row and add it to the all_rows.
How we will update row -
1. For each iteration of N, add 1 at index 0. Now iterate the rest of the elements in the list row, keep adding elements in pairs, starting from j=1, and set the sum at index j.
See the walk-through below

Output:

[1]
[1, 1]
[1, 2, 1]
[1, 3, 3, 1]
[1, 4, 6, 4, 1]