542. 01 Matrix

class Solution {
    // BFS Approach
    public int[][] updateMatrix(int[][] matrix) {

        Queue<int[]> queue = new LinkedList<>();
        for (int i = 0; i < matrix.length; i++) {
            for (int j = 0; j < matrix[0].length; j++) {
                if (matrix[i][j] == 0) {
                    queue.offer(new int[]{i, j});
                } else {
                    matrix[i][j] = Integer.MAX_VALUE;
                }
            }
        }
        
        int[][] dirs = {`{-1, 0},{1, 0},{0, -1},{0, 1}`};
        while (!queue.isEmpty()) {
            int[] cur = queue.poll();
            for (int[] dir : dirs) {
                int row = cur[0] + dir[0];
                int col = cur[1] + dir[1];
                if (row < 0 || row > matrix.length - 1 || col < 0 || col > matrix[0].length - 1) {
                    continue;
                }
                if (matrix[row][col] <= matrix[cur[0]][cur[1]] + 1) {
                    continue;
                }
                matrix[row][col] = matrix[cur[0]][cur[1]] + 1;
                queue.offer(new int[] {row, col});
            }
        }
        
        return matrix;
    }
}