Leetcode解题-Pascal Triangle

描述

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]
]

分析

比较简单，打印杨辉三角。

代码

Python

class Solution(object):
    def generate(self, numRows):
        """        :type numRows: int        :rtype: List[List[int]]        """
        :type numRows: int
        :rtype: List[List[int]]
        """
        if numRows == 0:
            return []
        rs = [[1]]
        for i in xrange(1, numRows):
            row = [1]
            for j in xrange(1, i):
                row.append(rs[i - 1][j - 1] + rs[i - 1][j])
            row.append(1)
            rs.append(row)
        return rs