（C#）顺时针/逆时针打印矩阵

题目描述：

思路 :

       建立一个list,遍历数组中行（列）添加到list中，然后改变数组的遍历方向顺时针（逆时针）旋转90度，知道遍历完成。

顺时针代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Test1
{
    //顺时针打印矩阵
    class OrderPrint
    {
        public static List<int> Solution(int[][] arrs)
        {
            List<int> list = new List<int>();
            int rows = arrs.Length;     //总行数
            int cols = arrs[0].Length;  //总列数
            if (rows == 0 || cols == 0 || arrs == null)
            {
                return null;
            }

            int start = 0;
            while (start * 2 < rows && start * 2 < cols)
            {
                PrintMatrix(list, rows, cols, arrs, start);
                start++;    //只算前面的索引
            }
            return list;
        }

        /// <summary>
        /// 用于将数组中的元素添加到链表中
        /// </summary>
        /// <param name="list"></param>
        /// <param name="rows"></param>
        /// <param name="cols"></param>
        /// <param name="arrs"></param>
        /// <param name="start"></param>
        /// <returns></returns>
        private static List<int> PrintMatrix(List<int> list,int rows,int cols,int[][] arrs,int start)
        {

            int endX = cols - 1 - start;    //得到这一行剩余的元素个数
            int endY = rows - 1 - start;    //得到这一列剩余的元素个数

            //将从左到右的元素加入链表
            for (int i = start; i <= endX; i++)
            {
                int number = arrs[start][i];
                list.Add(number);
            }

            //右侧从上往下将元素加入链表
            if (start < endY)
            {
                for (int i = start + 1; i <= endY; i++)
                {
                    int number = arrs[i][endX];
                    list.Add(number);
                }
            }

            //下方从右往左
            if (start < endX && start < endY)
            {
                for (int i = endX - 1; i >= start; i--)
                {
                    int number = arrs[endY][i];
                    list.Add(number);
                }
            }

            //左侧从下往上
            if (start < endX && start < endY - 1)
            {
                for (int i = endY - 1; i >= start + 1; i--)
                {
                    int number = arrs[i][start];
                    list.Add(number);
                }
            }
            return list;
        }
    }
}

 逆时针代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Test1
{
    //逆时针打印矩阵
    class ReOrderPrint
    {
        public static List<int> Solution(int[][] arrs)
        {
            List<int> list = new List<int>();
            int rows = arrs.Length;
            int cols = arrs[0].Length;
            if (arrs == null || rows == 0 || cols == 0)
            {
                return null;
            }

            int start = 0;
            while (start * 2 < rows && start * 2 < cols)
            {
                PrintMatrix(list, rows, cols, arrs, start);
                start++;
            }
            return list;
        }

        private static List<int> PrintMatrix(List<int> list, int rows, int cols, int[][] arrs, int start)
        {
            int endX = cols - 1 - start;
            int endY = rows - 1 - start;

            //从上到下
            for (int i = start; i <= endY; i++)
            {
                int number = arrs[i][start];
                list.Add(number);
            }

            //从左到右
            if (start < endY && start <endX)
            {
                for (int i = start + 1; i <= endX; i++)
                {
                    int number = arrs[endY][i];
                    list.Add(number);
                }
            }

            //从下到上
            if (start < endY && start < endX)
            {
                for (int i = endY - 1; i >= start; i--)
                {
                    int number = arrs[i][endX];
                    list.Add(number);
                }
            }

            //从右到左
            if (start < endX && start < endY)
            {
                for (int i = endX - 1; i > start; i--)
                {
                    int number = arrs[start][i];
                    list.Add(number);
                }
            }
            return list;
        }

    }
}

测试代码：

运行结果：