题目

输入一个矩阵，按照从外向里以顺时针的顺序依次打印出每一个数字。

示例

输入：matrix = [[1,2,3],[4,5,6],[7,8,9]]
输出：[1,2,3,6,9,8,7,4,5]

思考

• 设置上下左右边界，用for循环一圈一圈的进行顺时针输出

代码

class Solution {
    public int[] spiralOrder(int[][] matrix) {
        if (matrix.length == 0)
            return new int[0];
        int c = matrix[0].length, r = matrix.length;
        int[] array = new int[c * r];
        int count = 0, top = 0, bottom = r - 1,
                left = 0, right = c - 1;
        while (count != array.length) {
            for (int i = left; i <= right; i++) {
                if (count == array.length)
                    return array;
                array[count++] = matrix[top][i];
            }
            for (int i = top + 1; i <= bottom; i++) {
                if (count == array.length)
                    return array;
                array[count++] = matrix[i][right];
            }
            for (int i = right - 1; i > left; i--) {
                if (count == array.length)
                    return array;
                array[count++] = matrix[bottom][i];
            }
            for (int i = bottom; i > top; i--) {
                if (count == array.length)
                    return array;
                array[count++] = matrix[i][left];
            }
            left++;
            right--;
            top++;
            bottom--;
        }
        return array;
    }
}