劍指 Offer 29. 順時針列印矩陣

輸入一個矩陣，按照從外向裡以順時針的順序依次打印出每一個數字。

示例 1：

輸入：matrix = [[1,2,3],[4,5,6],[7,8,9]]
輸出：[1,2,3,6,9,8,7,4,5]
示例 2：

輸入：matrix = [[1,2,3,4],[5,6,7,8],[9,10,11,12]]
輸出：[1,2,3,4,8,12,11,10,9,5,6,7]

限制：

0 <= matrix.length <= 100
0 <= matrix[i].length <= 100
注意：本題與主站 54 題相同：https://leetcode-cn.com/problems/spiral-matrix/

通過次數177,812提交次數405,998

class Solution {
    public int[] spiralOrder(int[][] matrix) {
        if(matrix.length ==0 )return new int[]{};
        int[][] visit = new int [105][105];

        int n = matrix.length, m = matrix[0].length;
        int[] res = new int[n*m];//存放結果的arr
        int[][] dp={{0,1},{1,0},{0,-1},{-1,0}};
        int cnt = 0;
        int row = 0 , col = 0;
        int i = 0 ;//director 
        while(cnt<n*m)
        {
            res[cnt++] = matrix[row][col];
            visit[row][col] = 1;
            int drow = row+dp[i][0],dcol = col + dp[i][1];

            if(drow<0||drow>=n||dcol<0||dcol>=m||visit[drow][dcol]==1)
            {
            i = (i+1)%4;

            }
             row = row+dp[i][0];
             col = col + dp[i][1];

        }
        //123
        //456
        //789


  return res;



    }
}