题目描述
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.
import java.util.ArrayList; public class Solution { public ArrayList<Integer> printMatrix(int [][] matrix) { ArrayList<Integer> list = new ArrayList<>(); int r1 = 0; int r2 = matrix.length-1; int c1 = 0; int c2 = matrix[0].length-1; while(r1<=r2 && c1<=c2) { for(int i = c1; i <= c2; i++) list.add(matrix[r1][i]); for(int i = r1+1; i<= r2; i++) list.add(matrix[i][c2]); if(r1!=r2) for(int i = c2-1; i>= c1; i--) list.add(matrix[r2][i]); if(c1!=c2) for(int i = r2-1; i> r1; i--) list.add(matrix[i][c1]); r1++; r2--; c1++; c2--; } return list; } }