【Java】顺时针打印矩阵

清疚 2022-01-29 11:37 231阅读 0赞

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.

package 牛客;
    
    import java.util.ArrayList;
    import java.util.Scanner;
    
    public class 打印数组 {
        
        public static ArrayList<Integer> printMatrix(int[][] matrix) {
        
            ArrayList<Integer> a = new ArrayList<>();
            if (matrix == null) {
        
                return a;
            }
            int length = matrix.length;
            int len = matrix[0].length;
            if (length == 0 || len == 0) {
        
                return a;
            }
            int up = 0;
            int left = 0;
            int down = matrix.length - 1;
            int right = matrix[0].length - 1;
            while(left<=right && up<=down) {
        
    
                for (int i = left; i <= right; i++)
                    a.add(matrix[up][i]);
                up++;
                for (int i = up; i <= down; i++)
                    a.add(matrix[i][right]);
                right--;
                if (up - 1 != down) {
        
                    for (int i = right; i >= left; i--)
                        a.add(matrix[down][i]);
                }
                down--;
                if (left != right + 1) {
        
                    for (int i = down; i >= up; i--)
                        a.add(matrix[i][left]);
                }
                left++;
            }
            return a;
        }
        public static void main(String []args){
        
         int [][]a=new int[4][4];
            Scanner s=new Scanner(System.in);
        for(int i=0;i<4;i++){
        
            for(int j=0;j<4;j++){
        
                a[i][j]=s.nextInt();
            }
        }
            System.out.println(printMatrix(a));
        }
    }

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