73. Set Matrix Zeroes

Given an m x n matrix. If an element is 0, set its entire row and column to 0. Do it in-place.

Example 1:

Input: matrix = [[1,1,1],[1,0,1],[1,1,1]]
Output: [[1,0,1],[0,0,0],[1,0,1]]

Example 2:

Input: matrix = [[0,1,2,0],[3,4,5,2],[1,3,1,5]]
Output: [[0,0,0,0],[0,4,5,0],[0,3,1,0]]

找0的位置，行列都設0。

T: O(nˆ2), S: O(n)
class Solution:
    def setZeroes(self, matrix: List[List[int]]) -> None:
        """
        Do not return anything, modify matrix in-place instead.
        """
        row = set()
        column = set()
        
        for i in range(len(matrix)):
            for j in range(len(matrix[0])):
                if matrix[i][j] == 0: 
                    row.add(i)
                    column.add(j)  
        # record row and column has 0
        # print(row)
        # print(column)
        for i in row:
            for j in range(len(matrix[0])):
                matrix[i][j] = 0 # set row to 0 [i] [j]
                # print("r",i) # select number of row
                # print("c",j) # each column
        for i in column:
            for j in range(len(matrix)):
                matrix[j][i] = 0 # set column to 0 [j] [i] 
                # print("c",i) # select number of column
                # print("r",j) # each row

---

如果你覺得這篇文章很棒，請你不吝點讚 (ﾟ∀ﾟ)