693. Binary Number with Alternating Bits

Given a positive integer, check whether it has alternating bits: namely, if two adjacent bits will always have different values.

Example 1:

Input: 5
Output: True
Explanation:
The binary representation of 5 is: 101

Example 2:

Input: 7
Output: False
Explanation:
The binary representation of 7 is: 111.

Example 3:

Input: 11
Output: False
Explanation:
The binary representation of 11 is: 1011.

Example 4:

Input: 10
Output: True
Explanation:
The binary representation of 10 is: 1010.

class Solution:
    def hasAlternatingBits(self, n):
        """
        :type n: int
        :rtype: bool
        """
        s = bin(n)
        for i in range(2,len(s)-1):
            if s[i]=='1':
                if s[i+1]!='0':
                    return False
            else:
                if s[i+1]!='1':
                    return False
        return True