Leetcode 498. Diagonal Traverse

Posted 2021-08-26 SnailTyan

文章作者：Tyan
博客：noahsnail.com  |  CSDN  |  简书

1. Description

2. Solution

**解析：**Version 1，根据矩阵对角线的规律，对角线的数量为m+n-1，对角线的起点(左下到右上)为第一列加上最后一行的数据，顺序为行数一次加1，列不变，到左下角后，行数不变，列数依次加1，对角线上的数据依次为行减1，列加1。由于是对角线遍历是连续的，因此，行数加列数的和为奇数时，需要反转对角线数据。

• Version 1

class Solution:
    def findDiagonalOrder(self, mat: List[List[int]]) -> List[int]:
        m = len(mat)
        n = len(mat[0])
        result = []
        i = -1
        j = 0
        for _ in range(m+n-1):
            if i != m -1:
                i += 1
            else:
                j += 1
            current_row = i
            current_column = j
            temp = []
            while current_row > -1 and current_column < n:
                temp.append(mat[current_row][current_column])
                current_row -= 1
                current_column += 1
            if (i + j) % 2 == 1:
                result += temp[::-1]
            else:
                result += temp
        return result

Reference

1. https://leetcode.com/problems/diagonal-traverse/