问题：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，例如，如果输入如下4 X 4矩阵： 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 则依次打印出数字1,2,3,4,8,12,16,15,14,13,9,5,6,7,11,10.
解答：
public class Test {public void sortMatrix(int[][] matrix, int startRow, int startCol, int endRow, intendCol, ArrayList<Integer> result) {if (startRow < endRow && startCol < endCol) {// 从左到右for (int i = startCol; i <= endCol; i++) {result.add(matrix[startRow][i]);}// 从右上到右下for (int i = startRow + 1; i <= endRow; i++) {result.add(matrix[i][endCol]);}// 从右下到左下for (int i = endCol - 1; i > startCol; i--) {result.add(matrix[endRow][i]);}// 从左下到左上for (int i = endRow; i > startRow; i--) {result.add(matrix[i][startCol]);}sortMatrix(matrix, startRow + 1, startCol + 1, endRow - 1, endCol - 1,result);} else if (startRow == endRow && startCol < endCol) {for (int i = startCol; i <= endCol; i++) {result.add(matrix[startRow][i]);}} else if (startRow < endRow && startCol == endCol) {for (int i = startRow; i <= endRow; i++) {result.add(matrix[i][startCol]);}} else if (startRow == endRow && startCol == endCol) {result.add(matrix[startRow][startCol]);}}public ArrayList<Integer> printMatrix(int [][] matrix) {ArrayList<Integer> result = new ArrayList<>();if(matrix==null || matrix.length==0) { return result ; }int startRow = 0; // 开始行int startCol = 0; // 开始列int endRow = matrix.length - 1; // 结束行int endCol = matrix[0].length - 1; // 结束列sortMatrix(matrix, startRow, startCol,endRow, endCol, result);return result;}public static void main(String[] args) {int matrix[][] = {{1,2,3,4},{5,6,7,8},{9,10,11,12},{13,14,15,16}};Test solution = new Test();List<Integer> result = solution.printMatrix(matrix);for (int i = 0; i < result.size(); i++) {System.out.print(result.get(i));if (i != result.size() - 1) {System.out.print(",");}}}}
延伸：
中午是猿辅导水果时间，小猿会给每个同学发水果。猿辅导有一个矩形的办公区域，共有N 排，每排M个工位。平时小猿按照从第一排到最后一排的顺序发水果，某一天小猿突然发现似乎旋转着发水果是一种更有趣的方式，所以决定试试按照逆时针方向螺旋发水果。
已知每个工位有一个数字，表示该工位员工的工号，每个员工的工号不同。已知小猿从（0, 0）位置开始，按照逆时针螺旋的顺序发水果，请输出收到水果的员工工号序列。
解答：
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;public class Test {public void sortMatrix(int[][] matrix, int startRow, int startCol, int endRow, intendCol, ArrayList<Integer> result) {if (startRow < endRow && startCol < endCol) {// 从左上到左下for (int i = startRow; i <= endRow; i++) {result.add(matrix[i][startCol]);}// 从左下到右下for (int i = startCol + 1; i <= endCol; i++) {result.add(matrix[endRow][i]);}// 从右下到右上for (int i = endRow - 1; i >= startRow; i--) {result.add(matrix[i][endCol]);}// 从右上到左上for (int i = endCol - 1; i > startCol; i--) {result.add(matrix[startRow][i]);}sortMatrix(matrix, startRow + 1, startCol + 1, endRow - 1, endCol - 1,result);} else if (startRow == endRow && startCol < endCol) {for (int i = endCol; i >= startCol; i--) {result.add(matrix[startRow][i]);}} else if (startRow < endRow && startCol == endCol) {for (int i = endRow; i >= startRow; i--) {result.add(matrix[i][startCol]);}} else if (startRow == endRow && startCol == endCol) {result.add(matrix[startRow][startCol]);}}public ArrayList<Integer> printMatrix(int [][] matrix) {ArrayList<Integer> result = new ArrayList<>();if(matrix==null || matrix.length==0) { return result ; }int startRow = 0; // 开始行int startCol = 0; // 开始列int endRow = matrix.length - 1; // 结束行int endCol = matrix[0].length - 1; // 结束列sortMatrix(matrix, startRow, startCol,endRow, endCol, result);return result;}public static void main(String[] args) {int n = 0;int m = 0;int matrix[][];Scanner scanner = new Scanner(System.in);System.out.println("请输入行数及列数：");String[] firstLine = scanner.nextLine().split(" ");n = Integer.parseInt(firstLine[0]);m = Integer.parseInt(firstLine[1]);matrix = new int[n][m];Test test = new Test();for (int i = 0; i < n; i++) {String[] str = scanner.nextLine().split(" ");for (int j = 0; j < m; j++) {matrix[i][j] = Integer.parseInt(str[j]);}}// long startTime = System.currentTimeMillis(); //获取开始时间List<Integer> result = test.printMatrix(matrix);// long endTime = System.currentTimeMillis(); //获取结束时间// System.out.println("程序运行时间：" + (endTime - startTime) + "ms"); //输出程序运行时间for (int i = 0; i < result.size(); i++) {System.out.print(result.get(i));if (i != result.size() - 1) {System.out.print(",");}}}}