542. 01 Matrix

题目

Given a matrix consists of 0 and 1, find the distance of the nearest 0 for each cell.

The distance between two adjacent cells is 1.

Example 1:

Input:
0 0 0
0 1 0
0 0 0

Output:
0 0 0
0 1 0
0 0 0

Example 2:

Input:
0 0 0
0 1 0
1 1 1

Output:
0 0 0
0 1 0
1 2 1

Note:

1. The number of elements of the given matrix will not exceed 10,000.
2. There are at least one 0 in the given matrix.
3. The cells are adjacent in only four directions: up, down, left and right.

解题思路

见程序注释