Problem:
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.
思路：
Solution (C++):
bool hasAlternatingBits(int n) {
long long m = n >> 1;
return ((m+n) & (m+n+1)) == 0;
}
性能：
Runtime: 0 ms Memory Usage: 5.8 MB
思路：
Solution (C++):
bool hasAlternatingBits(int n) {
n ^= n >> 2;
return (n & (n-1)) == 0;
}
性能：
Runtime: 0 ms Memory Usage: 5.9 MB
