59. 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 ]

]

#include<iostream>
#include<vector>
using namespace std;
class Solution {
public:
vector<vector<int> > generateMatrix(int n)
{
vector<vector<int> >result(n,vector<int>(n,0));//注意二维vector初始化
if(0==n)
return result;
int count=1;
int x=0,y=0;
result[0][0]=count;
while(count<n*n)
{
while(y+1<n&&!result[x][y+1])
result[x][++y]=++count;
while(x+1<n&&!result[x+1][y])
result[++x][y]=++count;
while(y-1>=0&&!result[x][y-1])
result[x][--y]=++count;
while(x-1>=0&&!result[x-1][y])
result[--x][y]=++count;
}
return result;
}
};
int main()
{
vector<vector<int> >ret;
int N;
cin>>N;
Solution solve;
ret=solve.generateMatrix(N);
int i,j;
for(i=0;i<N;i++)
{
for(j=0;j<N;j++)
cout<<ret[i][j]<<' ';
cout<<endl;
}
return 0;
}