헬리컬 매트릭스(시계 방향으로 내회전)

import java.util.Arrays;

public class SpiralMatrix {
	/**
	 * @param args
	 * @author zhangshaonian
	 */
	public static void main(String[] args) {
		int[][] base = spiralMatrix(3);
		for (int i = 0; i < base.length; i++) {
			System.out.println(Arrays.toString(base[i]));
		}

	}

	private static int[][] spiralMatrix(int num) {
		int size = num;
		int[][] m = new int[size][size];
		int circleNum = num / 2 + num % 2;//  
		int count = 1;
		int startX = 0;
		int startY = 0;
		for (int i = 0; i < circleNum; i++) {
			int subSize = num - 2 * i;//         
			//    
			for (int j = 0; j < subSize; j++) {

				if (j == subSize - 1) {
					m[startX][startY] = count++;
					startX++;//     
				} else {
					m[startX][startY++] = count++;
				}

			}
			//    
			for (int j = 0; j < subSize - 1; j++) {
				if (j == subSize - 2) {
					m[startX][startY] = count++;
					startY--;//     
				} else {
					m[startX++][startY] = count++;
				}

			}
			//    
			for (int j = 0; j < subSize - 1; j++) {
				if (j == subSize - 2) {
					m[startX][startY] = count++;
					startX--;//     
				} else {
					m[startX][startY--] = count++;
				}

			}
			//    
			for (int j = 0; j < subSize - 2; j++) {
				if (j == subSize - 3) {
					m[startX][startY] = count++;
					startY++;//     
				} else {
					m[startX--][startY] = count++;
				}

			}

		}
		return m;

	}
}