leetcode693

class Solution {
public:
    bool hasAlternatingBits(int n) {
        int last = -;
        while (n)
        {
            int x = n & ;
            if (last == -)
            {
                last = x;
            }
            else
            {
                if (x == last)
                {
                    return false;
                }
                else
                {
                    last = x;
                }
            }
            n >>= ;//n右移1位
        }
        return true;
    }
};