CODE 74: 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 ]
]

	public int[][] generateMatrix(int n) {
		// IMPORTANT: Please reset any member data you declared, as
		// the same Solution instance will be reused for each test case.
		int[][] matrix = new int[n][n];
		int number = 1;
		int halfCol = (n - 1) / 2;
		int halfRow = (n - 1) / 2;
		int col = 0;
		int row = 0;
		while (row <= halfRow && col <= halfCol) {
			for (int i = col; i < n - col; i++) {
				matrix[row][i] = number++;
			}
			for (int i = row + 1; i < n - row; i++) {
				matrix[i][n - col - 1] = number++;
			}
			if (row != n - row - 1) {
				for (int i = n - col - 2; i >= col; i--) {
					matrix[n - row - 1][i] = number++;
				}
			}

			if (col != n - col - 1) {
				for (int i = n - row - 2; i >= row + 1; i--) {
					matrix[i][col] = number++;
				}
			}
			row++;
			col++;
		}
		return matrix;
	}