题意

题意

Given an integer rowIndex, return the rowIndexth row of the Pascal’s triangle. Notice that the row index starts from 0.

Example 1:
Input: rowIndex = 3
Output: [1,3,3,1]

Example 2:
Input: rowIndex = 0
Output: [1]

Example 3:
Input: rowIndex = 1
Output: [1,1]

思路

• 递归 + 暴力找规律
• 同118，只返回指定行结果

class Solution(object):
    def getRow(self, rowIndex):
        """
        :type rowIndex: int
        :rtype: List[int]
        """
        res = []
        for i in range(rowIndex+1): #注意要走到rowIndex
            res.append([1] * (i + 1))
            for j in range(1, i):
                res[i][j] = res[i-1][j-1]+res[i-1][j]
        return res[rowIndex]

分析:

• Time: O(n^2)
• Space: O(n)