Given a positive integer, output its complement number. The complement strategy is to flip the bits of its binary rePResentation.

Note:

Example 1:

Input: 5Output: 2Explanation: 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: 1Output: 0Explanation: The binary representation of 1 is 1 (no leading zero bits), and its complement is 0. So you need to output 0.
思路：
數清leading zeros，翻轉位，然后清掉不需要的位。
題解：
int findComplement(int num) {    int zeros(0);    for(; zeros < 32; ++zeros) {        if (num & (1 << 31)) {            break;        }        num <<= 1;    }    num = ~num;    for(; zeros > 0; --zeros) {        num >>= 1;    }    return num;}