【leetcode】Spiral Matrix II

Spiral Matrix II

Given an integer n, generate a square matrix filled with elements from 1 to n² in spiral order.

For example,
Given n = 3,

You should return the following matrix:

[

 [ 1, 2, 3 ],

 [ 8, 9, 4 ],

 [ 7, 6, 5 ]

]

 

与Spiral Matrix类似：

 

 1 class Solution {

 2 public:

 3     vector<vector<int> > generateMatrix(int n) {

 4        

 5         int x1=0;

 6         int y1=0;

 7         int x2=n-1;

 8         int y2=n-1;

 9        

10         int count=0;

11         vector<vector<int>> result(n,vector<int>(n));

12         while(count<n*n)

13         {

14            

15             for(int j=y1;j<=y2;j++)

16             {

17                 count++;

18                 result[x1][j]=count;

19             }              

20             for(int i=x1+1;i<=x2;i++)

21             {

22                 count++;

23                 result[i][y2]=count;

24             }

25            

26             for(int j=y2-1;j>=y1;j--)

27             {

28                 count++;

29                 result[x2][j]=count;

30             }

31            

32             for(int i=x2-1;i>x1;i--)

33             {

34                 count++;

35                 result[i][x1]=count;

36             }

37            

38             x1++;y1++;x2--;y2--;

39         }

40        

41         return result;

42        

43        

44     }

45 };