编程练习（三）

题目：一个组数：122345这6个数，打印出它所有可能的组合；要求4不能在第3位，3和5不能相连

public class ComboTest {
	public static void main(String... args) {
		int[] inArrays = {1, 2, 2, 3, 4, 5};
		int[] outArrays = new int[inArrays.length];
		go(inArrays[0], 1, inArrays, outArrays);
	}
	
	public static void go(int preNum, int level, int[] inArrays, int[] outArrays) {
		List<Integer> inList = new ArrayList<Integer>();
		for (int i = 0; i < inArrays.length; i++) {
			if (inList.contains(inArrays[i])) continue;
			if (level == 4 && inArrays[i] == 3) continue;
			if ((preNum == 3 && inArrays[i] == 5) 
					|| (preNum == 5 && inArrays[i] == 3)) 
				continue;
			outArrays[level - 1] = inArrays[i];
			inList.add(inArrays[i]);
			if (level == outArrays.length) {
				System.out.println(Arrays.toString(outArrays));
			} else {
				go(inArrays[i], level + 1, createNewArray(inArrays, i), outArrays);
			}
		}
	}

	private static int[] createNewArray(int[] inArrays, int index) {	
		int[] newArrays = new int[inArrays.length - 1];
		int newIndex = 0;
		for (int i = 0; i < inArrays.length; i++) {
			if (i == index) continue;
			newArrays[newIndex] = inArrays[i];
			newIndex++;
		}
		return newArrays;
	}
}