Problem Statement

Given a 0-indexed m x n binary matrix, return the minimum number of operations needed to remove all 1's from the matrix.

In one operation, you can choose any i and j such that:

• 0 <= i < m
• 0 <= j < n
• grid[i][j] == 1

and change the values of all cells in row i and column j to zero.

Examples

Example 1:

• Input:

[[1,0,1],
 [1,1,1],
 [0,1,0]]

• Expected Output: 2
• Justification: First, choose the cell [0,2], and perform operations. The matrix becomes [[0,0,0],[1,1,0],[0,1,0]]. Then, choose the middle cell [1,1]. The matrix becomes all zeros.

Example 2:

• Input:

[[0,1,0],
 [1,1,1],
 [0,1,0]]

• Expected Output: 1
• Justification: A single operation on the middle cell (cell [1,1]) flips all the 1s to 0s. Thus, only 1 operation is needed.

Example 3:

• Input:

[[1,1,0,0],
 [1,0,1,0],
 [0,1,1,0],
 [0,0,0,1]]

• Expected Output: 3
• Justification: Choose (0, 1), (1, 2), and (3, 3) cells respectively, and convert all values of respected columns and rows to zero.

Try it yourself

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