problem
693. Binary Number with Alternating Bits
solution1:
class Solution { public: bool hasAlternatingBits(int n) { int bit = -1; while(n>0) { /* errr... if(n&1 && bit==1) return false; else if(n&1) bit = 1; if(n&1==0 && bit==0) return false; else if(n&1==0) bit = 0; */ if(n&1==1) { if(bit==1) return false; bit = 1; } else { if(bit==0) return false; bit = 0; } n >>= 1;//err. } return true; } };
solution2:
通过异或操作判断最低位是否在0/1之间转换进行。
class Solution { public: bool hasAlternatingBits(int n) { int d = (n&1); while((n&1)==d) { d ^= 1;// n >>= 1; } return n==0; } };
参考
1. Leetcode_easy_693. Binary Number with Alternating Bits;
2. Grandyang;
完