leetcode1329. Sort the Matrix Diagonally

Posted 2021-03-13 seyjs

题目如下：

Given a m * n matrix mat of integers, sort it diagonally in ascending order from the top-left to the bottom-right then return the sorted array.

Example 1:

Input: mat = [[3,3,1,1],[2,2,1,2],[1,1,1,2]]
Output: [[1,1,1,1],[1,2,2,2],[1,2,3,3]]

Constraints:

• m == mat.length
• n == mat[i].length
• 1 <= m, n <= 100
• 1 <= mat[i][j] <= 100

解题思路：分别对每个对角线单独排序吧，简单直接。

代码如下：

class Solution(object):
    def diagonalSort(self, mat):
        """
        :type mat: List[List[int]]
        :rtype: List[List[int]]
        """
        for i in range(len(mat[0])):
            arr = []
            x,y = 0,i
            while x < len(mat) and y < len(mat[0]):
                arr.append(mat[x][y])
                x += 1
                y += 1
            arr.sort()
            
            x,y = 0,i
            while x < len(mat) and y < len(mat[0]):
                mat[x][y] = arr.pop(0)
                x += 1
                y += 1
            
        
        for i in range(1,len(mat)):
            arr = []
            x,y = i,0
            while x < len(mat) and y < len(mat[0]):
                arr.append(mat[x][y])
                x += 1
                y += 1
            arr.sort()
            
            x,y = i,0
            while x < len(mat) and y < len(mat[0]):
                mat[x][y] = arr.pop(0)
                x += 1
                y += 1
        return mat