Pascal's Triangle - LeetCode

I have not done any coding problem recently. Here is simple problem with a simple solution. https://leetcode.com/problems/pascals-triangle/

Given numRows, generate the first numRows of Pascal's triangle.
For example, given numRows = 5,
Return

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

The idea here is every row in the triangle is generated based on the row above it. For example, the 3rd row [1, 2, 1] can be generated by going through each item in the row [1, 1], add pre number or 0 for the first item and itself, so it will be 0+1 = 1, 1+1=2, then append 1 in the list.

The code is pretty straightforward.