LeetCode 542. 01 Matrix

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.

BFS计算，算是经典题目；得多练练这个。

Runtime: 13 ms, faster than 77.51% of Java online submissions for 01 Matrix.

Memory Usage: 44.3 MB, less than 92.71% of Java online submissions for 01 Matrix.