[LeetCode]59 Spiral Matrix II

public class Solution {
public int[][] generateMatrix(int n)
{
int[][] matrix = new int

;
int num = 1;

int len = n;
int x = 0;
while (n > 0)
{
if (n == 1)
{
matrix[x][x] = num;
break;
}

// Circle
// up
for (int i = 0 ; i < n - 1 ; i ++)
{
matrix[x][x + i] = num;
num ++;
}

// right
for (int i = 0 ; i < n - 1 ; i ++)
{
matrix[x + i][len - 1 - x] = num;
num++;
}

// down
for (int i = 0 ; i < n - 1 ; i ++)
{
matrix[len - 1 - x][len - 1 - x - i] = num;
num ++;
}

// left
for (int i = 0 ; i < n - 1 ; i ++)
{
matrix[len - 1 - x - i][x] = num;
num ++;
}

x ++;
n -= 2;
}

return matrix;
}
}