Given a positive integer, output its complement number. The complement strategy is to flip the bits of its binary representation.
Note:
The given integer is guaranteed to fit within the range of a 32-bit signed integer.You could assume no leading zero bit in the integer’s binary representation.Example 1:
Input: 5 Output: 2 Explanation: The binary representation of 5 is 101 (no leading zero bits), and its complement is 010. So you need to output 2.Example 2:
Input: 1 Output: 0 Explanation: The binary representation of 1 is 1 (no leading zero bits), and its complement is 0. So you need to output 0. /* * 【题目分析】 给定一个正整数，对该数的二进制表示形式，从最高位的1开始向后按位取反。 【思路】 如果我们能知道该数最高位的1所在的位置，就可以构造一个长度和该数据所占位置一样长的一个掩码mask， 然后概述和mask进行异或即可。 例如：5的二进制是101，我们的构造的掩码为mask=111，两者异或则为010，即是所要的结果。 */ public int findComplement(int num) { int temp=num; int mask=1; while(temp>0) { temp =temp >> 1; mask=mask << 1; } return num^(mask-1); }