题解 | #顺时针打印矩阵#

import java.util.ArrayList;
public class Solution {
    public ArrayList<Integer> printMatrix(int [][] matrix) {
       int up=0;
       int left=0;
       int down=matrix.length-1;
       int right=matrix[0].length-1;
       ArrayList list = new ArrayList(){};
       while(true){
           for(int i = left;i<=right;i++){
               list.add(matrix[up][i]);
           }
           up++;
           if(up>down) break;
           for(int i=up;i<=down;i++){
               list.add(matrix[i][right]);
           }
           right--;
           if(right<left) break;
           for(int i=right;i>=left;i--){
               list.add(matrix[down][i]);
           }
           down--;
           if(up>down) break;
           for(int i=down;i>=up;i--){
               list.add(matrix[i][left]);
           }
           left++;
           if(right<left) break;
       }
        return list;
    }
}