Spiral Matrix

题目原型：

Given a matrix of m x n elements (m rows, n columns), return all elements of the matrix in spiral order.

For example,
Given the following matrix:

[
 [ 1, 2, 3 ],
 [ 4, 5, 6 ],
 [ 7, 8, 9 ]
]

You should return [1,2,3,6,9,8,7,4,5].

基本思路：

本题思路可参考，旋转矩阵

	public ArrayList<Integer> spiralOrder(int[][] matrix)
	{
		ArrayList<Integer> list = new ArrayList<Integer>();
		if (matrix == null || matrix.length == 0)
			return list;
		int layer = 0;// 围成的层数

		int row = 0;
		int column = 0;

		int lenRow = matrix.length;
		int lenCol = matrix[0].length;

		int min = lenRow < lenCol ? lenRow : lenCol;
		
		//单独处理行或列为1的情况
		if(min==1)
		{
			if(lenCol==1)
			{
				for(int index = 0;index<lenRow;index++)
					list.add(matrix[index][lenCol-1]);
			}
			else
				for(int index = 0;index<lenCol;index++)
					list.add(matrix[lenRow-1][index]);
			
			return list;
		}
		while (true)
		{
			while (column < lenCol - layer)
			{
				list.add(matrix[row][column]);
				column++;
			}
			column--;// 退回来
			row++;// 开始
			while (row < lenRow - layer)
			{
				list.add(matrix[row][column]);
				row++;
			}
			row--;
			column--;
			while (column >= layer)
			{
				list.add(matrix[row][column]);
				column--;
			}
			column++;
			row--;
			layer++;// 将圈数加一
			while (row >= layer)
			{
				list.add(matrix[row][column]);
				row--;
			}

			if (layer >= min / 2)
				break;
			// 重新分配起点
			row = layer;
			column = layer;
		}
		// 处理最后一圈
		if (lenRow % 2 == 0 && lenCol % 2 != 0)
		{
			column = lenCol / 2;
			for (int index = layer; index < lenRow - layer; index++)
			{
				list.add(matrix[index][column]);
			}
		}

		if (lenRow % 2 != 0 && lenCol % 2 == 0)
		{
			row = lenRow / 2;
			for (int index = layer; index < lenCol - layer; index++)
			{
				list.add(matrix[row][index]);
			}
		}

		if (lenRow % 2 != 0 && lenCol % 2 != 0)
		{
			if (lenRow < lenCol)
			{
				row = lenRow / 2;
				for (int index = layer; index < lenCol - layer; index++)
				{
					list.add(matrix[row][index]);
				}
			}
			else
			{
				column = lenCol / 2;
				for (int index = layer; index < lenRow - layer; index++)
				{
					list.add(matrix[index][column]);
				}
			}
		}
		return list;
	}

Spiral Matrix,布布扣,bubuko.com

Spiral Matrix

原文：http://blog.csdn.net/cow__sky/article/details/21185085