1 class Solution  2 { 3 public: 4     vector
     
      
       > generateMatrix(int n)  5     { 6         vector
       
        
         > res(n,vector
         
           (n,0)); 7         int right=n-1,down=n-1; 8         int left=0,up=0,k=1; 9         int lim=n*n;10         while(k<=lim)11         {12             for(int x=left;x<=right;x++)13                 res[up][x]=k++;14             up++;15             for(int y=up;y<=down;y++)16                 res[y][right]=k++;17             right--;18             for(int x=right;x>=left;x--)19                 res[down][x]=k++;20             down--;21             for(int y=down;y>=up;y--)22                 res[y][left]=k++;23             left++;24         }25         return res;26     }27 };
         
        
       
      
     

和螺旋输出相反，这个直接螺旋填写即可