大于某数的相邻两位数不同的最小整数

题目地址：http://news.bangkaow.com/news/20110812/227061.html

 

题目简述：求大于某个整数n的相邻两位数不同的最小的整数。

 

public class test {

	public static void main(String[] args) {
		// int num = (int) (Math.random() * 10000000);
		int num = 9899;
		System.out.println(num);
		System.out.println(getResult(num));
	}

	private static int getResult(int num) {
		char[] array = String.valueOf(num).toCharArray();
		int length = array.length;
		int from = 1;
		while (from < length) {
			// 找到首个跟上一位重复的位置
			if (array[from] == array[from - 1]) {
				// 回退，找得首个不为9的位置
				while (from >= 0 && array[from] == '9') {
					from--;
				}
				// 如果第一位就是9，原数前面加一位1
				if (from < 0) {
					array = ('1' + String.valueOf(num)).toCharArray();
					length++;
					from = 1;
					break;
				}
				array[from] = (char) (array[from] + 1);
				// 如果改改后与上一位不同
				if (array[from] != array[from - 1]) {
					from = from + 1;
					break;
				}
			} else {
				from++;
			}
		}
		// 如果原数无重复，则+1
		if (from == length) {
			num++;
			array = String.valueOf(num).toCharArray();
			length = array.length;
			if (length > 1 && array[length - 2] == array[length - 1]) {
				return getResult(num);
			}
			return num;
		}

		// 从改变位的下一位开始，0、1序列填充
		char c = '0';
		int s = '0' + '1';
		for (; from < length; from++) {
			array[from] = c;
			c = (char) (s - c);
		}

		return Integer.valueOf(String.valueOf(array));
	}
}