LintCode刷题笔记-- Count1 binary

位运算

描述：

Count how many 1 in binary representation of a 32-bit integer.

解题思路：

统计一个int型的数的二进制表现形式中1的个数
1.与check power of 2中的解题形式非常相似，同样利用num&(num-1) 的结果来检查num中二进制形式上1的个数，区别在于Check Power of 2 是来检查是否存在1，而这一题主要是检查有几个1。
2. 此题可以利用 num = num&(num-1) 每次进行与运算可以消除一个1，在num等于0之前就可以计算出二进制序列中存在几个1了。

参考代码：

http://www.jiuzhang.com/solutions/count-1-in-binary/

时间： 2024-07-28 18:14:45

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