LeetCode Weekly 124 - 994. Rotting Oranges

994. Rotting Oranges
In a given grid, each cell can have one of three values: the value 0 representing an empty cell; the value 1 representing a fresh orange; the value 2 representing a rotten orange. Every minute, any fresh orange that is adjacent (4-directionally) to a rotten orange becomes rotten. Return the minimum number of minutes that must elapse until no cell has a fresh orange. If this is impossible, return -1 instead.

	public class RottingOranges_994 {
	private final static Logger logger = LoggerFactory.getLogger(RottingOranges_994.class);
	public static void main(String[] args) {
	RottingOranges_994 thisClass = new RottingOranges_994();
	thisClass.testRottingOranges_994();
	}
	private void testRottingOranges_994() {
	logger.info("result {} v.s. {}", "4", orangesRotting(new int[][]{
	{2, 1, 1}, {1, 1, 0}, {0, 1, 1}
	}));
	logger.info("result {} v.s. {}", "-1", orangesRotting(new int[][]{
	{2, 1, 1}, {0, 1, 1}, {1, 0, 1}
	}));
	logger.info("result {} v.s. {}", "0", orangesRotting(new int[][]{
	{0, 2}
	}));
	}
	public int orangesRotting(int[][] grid) {
	// filter abnormal cases
	if (grid == null || grid.length == 0 || grid[0] == null || grid[0].length == 0) {
	return 0;
	}
	// searching logic
	int m = grid.length, n = grid[0].length;
	List<Point> list = new ArrayList<>();
	for (int i = 0; i < m; i++) {
	for (int j = 0; j < n; j++) {
	if (grid[i][j] == 2) {
	list.add(new Point(i, j));
	}
	}
	}
	int turns = 0;
	boolean isMakingProgress = true;
	while (isMakingProgress) {
	isMakingProgress = false;
	List<Point> tmpList = new ArrayList<>();
	for (Point point : list) {
	for (int t = 0; t < 4; t++) {
	int x = dx[t] + point.x;
	int y = dy[t] + point.y;
	if (x >= 0 && y >= 0 && x < m && y < n) {
	if (grid[x][y] == 1) {
	grid[x][y] = 2;
	tmpList.add(new Point(x, y));
	isMakingProgress = true;
	}
	}
	}
	}
	if (isMakingProgress) {
	list.addAll(tmpList);
	turns++;
	}
	}
	// return the final result
	return hasFresh(grid) ? -1 : turns;
	}
	int[] dx = new int[]{0, 0, 1, -1};
	int[] dy = new int[]{1, -1, 0, 0};
	private boolean hasFresh(int[][] grid) {
	int m = grid.length, n = grid[0].length;
	for (int i = 0; i < m; i++) {
	for (int j = 0; j < n; j++) {
	if (grid[i][j] == 1) {
	return true;
	}
	}
	}
	return false;
	}
	private class Point {
	int x;
	int y;
	public Point(int x, int y) {
	this.x = x;
	this.y = y;
	}
	}
	private static class MyLogger {
	private static final boolean isDebugging = false;
	private static final boolean isInfoing = true;
	private static final String DEBUG = "[DEBUG]";
	private static final String INFO = "[INFO]";
	static void debug(Object message) {
	if (isDebugging) {
	System.out.println(DEBUG + " = " + message);
	}
	}
	static void info(Object message) {
	if (isInfoing) {
	System.out.println(INFO + " = " + message);
	}
	}
	static void debug() {
	if (isDebugging) {
	System.out.println(DEBUG + " = ");
	}
	}
	static void info() {
	if (isInfoing) {
	System.out.println(INFO + " = ");
	}
	}
	}
	}

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