Given a matrix of m x n elements (m rows, n columns), return all elements of the matrix in spiral order.

For example,

Given the following matrix:

[ [ 1, 2, 3 ], [ 4, 5, 6 ], [ 7, 8, 9 ]]

You should return [1,2,3,6,9,8,7,4,5].

class Solution {public:    vector
     
       spiralOrder(vector
      
       
         > &matrix) {        vector
        
          ans;        if(matrix.size()==0) return ans;        int m=matrix.size()-1;        int n=matrix[0].size()-1;        int x=0;        int y=0;        int i;        while(m>=x&&n>=y)        {            for(i=y;i<=n;i++) ans.push_back(matrix[x][i]);             for(i=x+1;i<=m;i++) ans.push_back(matrix[i][n]);             if(x!=m) for(i=n-1;i>=y;i--) ans.push_back(matrix[m][i]);             if(y!=n) for(i=m-1;i>x;i--) ans.push_back(matrix[i][y]);             x++;y++;m--;n--;        }        return ans;    }};