Pascal's Triangle

## Problem Given an integer `numRows`, return the first `numRows` of **Pascal's triangle**. In Pascal's triangle, each number is the sum of the two numbers directly above it. The edges of each row are always 1. ``` [1] [1,1] [1,2,1] [1,3,3,1] [1,4,6,4,1] ``` ## Examples **Example 1:** ``` Input: numRows = 5 Output: [[1],[1,1],[1,2,1],[1,3,3,1],[1,4,6,4,1]] ``` **Example 2:** ``` Input: numRows = 1 Output: [[1]] ``` ## Hints - Start with the base case: the first row is always `[1]`. - For each subsequent row, the first and last elements are 1. - Every interior element at index `j` equals `prev_row[j-1] + prev_row[j]`.