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.
分一圈一圈的打印
import java.util.ArrayList; public class Solution { ArrayList<Integer> list = new ArrayList<Integer>(); public ArrayList<Integer> printMatrix(int[][] matrix) { int row = matrix.length;// 行数 int col = matrix[0].length;// 列数 if (matrix == null || row <= 0 || col <= 0) { return null; } int start = 0; while (row > start * 2 && col > start * 2) { printCircle(matrix, row, col, start); start++; } return list; } private ArrayList<Integer> printCircle(int[][] matrix, int row, int col, int start) { int endx = col - 1 - start; int endy = row - 1 - start; // 从左到右打印一行 for (int i = start; i <= endx; i++) { list.add(matrix[start][i]); } // 从上到下打印一列 if (endy > start) { for (int i = start+1; i <= endy; i++) { list.add(matrix[i][endx]); } } // 从右到左打印一行 if (endx > start && endy > start) { for (int i = endx-1; i >= start; i--) { list.add(matrix[endy][i] ); } } // 从下到上打印一列 if (endx > start && endy - 1 > start) { for (int i = endy-1; i >= start+1; i--) { list.add(matrix[i][start]); } } return list; } }