0542. 01 Matrix

https://leetcode.com/problems/01-matrix

Description

Given an m x n binary matrix mat, return the distance of the nearest 0 for each cell.

The distance between two adjacent cells is 1.

Example 1:

**Input:** mat = [[0,0,0],[0,1,0],[0,0,0]]
**Output:** [[0,0,0],[0,1,0],[0,0,0]]

Example 2:

**Input:** mat = [[0,0,0],[0,1,0],[1,1,1]]
**Output:** [[0,0,0],[0,1,0],[1,2,1]]

Constraints:

• m == mat.length

• n == mat[i].length

• 1 <= m, n <= 104

• 1 <= m * n <= 104

• mat[i][j] is either 0 or 1.

• There is at least one 0 in mat.

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