蛇形矩阵

public class Test{
public static void main(String args[]){
Scanner reader = new Scanner(System.in);
int N = reader.nextInt();
int[][] array = new int

;
int i=0,j=0,k=N-1,n=0;
int num=1;
while(i<k){
for(;j<k;j++){
array[i][j] = num++;
}
for(;i<k;i++){
array[i][j] = num++;
}
for(;j>n;j--){
array[i][j] = num++;
}
for(;i>n;i--){
array[i][j] = num++;
}
i++;
j++;
k--;
n++;
}
if(i==k){
array[i][i] = num;
}
for(int x=0;x<N;x++)
for(int y=0;y<N;y++)
System.out.print(array[x][y]+" ");
System.out.println();
}
}