Spiral Matrix

public class Solution {
    public ArrayList<Integer> spiralOrder(int[][] matrix) {
		// Start typing your Java solution below
		// DO NOT write main() function
		ArrayList<Integer> res = new ArrayList<Integer>();
		int m = matrix.length;
		if (m == 0)
			return res;
		int n = matrix[0].length;
		if (n == 0)
			return res;
		int min = m < n ? m : n;
		int layer = min / 2;
		for (int i = 0; i < layer; i++) {
			for (int j = i; j < n - 1 - i; j++)
				res.add(matrix[i][j]);
			for (int j = i; j < m - 1 - i; j++)
				res.add(matrix[j][n - 1 - i]);
			for (int j = n - 1 - i; j > i; j--)
				res.add(matrix[m - 1 - i][j]);
			for (int j = m - 1 - i; j > i; j--)
				res.add(matrix[j][i]);
		}
		if (min % 2 == 1) {
			if (m > n)
				for (int i = layer; i <= m - 1 - layer; i++)
					res.add(matrix[i][n / 2]);
			else
				for (int i = layer; i <= n - 1 - layer; i++)
					res.add(matrix[m / 2][i]);
		}
		return res;
	}
}

public class Solution {
    public ArrayList<Integer> spiralOrder(int[][] matrix) {
		ArrayList<Integer> res = new ArrayList<Integer>();
		if (matrix.length == 0)
			return res;
		int beginX = 0, endX = matrix[0].length - 1;
		int beginY = 0, endY = matrix.length - 1;
		while (true) {
			// From left to right
			for (int i = beginX; i <= endX; ++i)
				res.add(matrix[beginY][i]);
			if (++beginY > endY)
				break;
			// From top down
			for (int i = beginY; i <= endY; ++i)
				res.add(matrix[i][endX]);
			if (beginX > --endX)
				break;
			// From right to left
			for (int i = endX; i >= beginX; --i)
				res.add(matrix[endY][i]);
			if (beginY > --endY)
				break;
			// From bottom up
			for (int i = endY; i >= beginY; --i)
				res.add(matrix[i][beginX]);
			if (++beginX > endX)
				break;
		}
		return res;
	}
}