###118. Pascal's Triangle 打印杨辉三角
###Contents
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]
]
###Difficulty Easy
###Tags Array
###Similar Problems (E) Pascal's Triangle II