LeetCode | Spiral Matrix II

題目

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

For example,
Given n = 3,

[
 [ 1, 2, 3 ],
 [ 8, 9, 4 ],
 [ 7, 6, 5 ]
]

和Spiral Matrix一樣的思路，但是矩陣是方陣了，代碼會更簡潔些。

代碼

public class SpiralMatrixII {
	public int[][] generateMatrix(int n) {
		int[][] matrix = new int[n][n];
		int min = 0;
		int max = n - 1;
		int num = 1;
		while (min <= max) {
			for (int i = min; i <= max; ++i) {
				matrix[min][i] = num++;
			}
			for (int i = min + 1; i <= max; ++i) {
				matrix[i][max] = num++;
			}
			if (min != max) {
				for (int i = max - 1; i >= min; --i) {
					matrix[max][i] = num++;
				}
			}
			for (int i = max - 1; i > min; --i) {
				matrix[i][min] = num++;
			}

			++min;
			++max;
		}
		return matrix;
	}
}