Pascal's Triangle
EasyMath
Description
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.
Examples
Input:
numRows = 5Output:
[[1],[1,1],[1,2,1],[1,3,3,1],[1,4,6,4,1]]Explanation:
Each row starts and ends with 1. Interior values are sums of adjacent values above: row 2 has 2=1+1, row 3 has 3=1+2 and 3=2+1, row 4 has 4=1+3, 6=3+3, 4=3+1.
Input:
numRows = 1Output:
[[1]]Explanation:
The first row of Pascal's triangle always contains just [1]. This is the base case from which all subsequent rows are built.
Input:
numRows = 4Output:
[[1],[1,1],[1,2,1],[1,3,3,1]]Explanation:
The first 4 rows of Pascal's triangle. Row 0 has [1], row 1 has [1,1], row 2 has [1,2,1] where 2 = 1+1, and row 3 has [1,3,3,1] where the first 3 = 1+2 and the second 3 = 2+1 from the row above.
Constraints
- •
1 ≤ numRows ≤ 30