leetcode讲解--693. Binary Number with Alternating Bits

题目Given a positive integer, check whether it has alternating bits: namely, if two adjacent bits will always have different values.Example 1:Input: 5Output: TrueExplanation:The binary representation of 5 is: 101Example 2:Input: 7Output: FalseExplanation:The binary representation of 7 is: 111.Example 3:Input: 11Output: FalseExplanation:The binary representation of 11 is: 1011.Example 4:Input: 10Output: TrueExplanation:The binary representation of 10 is: 1010.题目地址讲解这一题的意思是判断一个整数的二进制形式，是否是0和1互相间隔排列的。题目挺简单的，但我想做的是空间O(1)。所以我用两个变量来存储遍历过程中需要保存的前一位和后一位，然后设置一个首次访问flag。遍历一遍二进制，结果就出来了。java代码class Solution { public boolean hasAlternatingBits(int n) { if(n<=2){ return true; } int temp = n; int now = 0; int previous = 0; boolean flag = true; while(temp>0){ if(flag){ now = temp%2; temp >>= 1; flag = false; }else{ previous = now; now = temp%2; if(previous==now){ return false; } temp >>= 1; } } return true; }}