476. 求二进制的补数 Number Complement

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

Note:

  1. The given integer is guaranteed to fit within the range of a 32-bit signed integer.
  2. 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.


  1. public int FindComplement(int num) {
  2. int number = 0;
  3. string s = "";
  4. while (num > 0)
  5. {
  6. s = ((num % 2) ^ 1).ToString() + s;
  7. num /= 2;
  8. }
  9. double pow = 0;
  10. for (int i = s.Length - 1; i >= 0; i--)
  11. {
  12. number += (Convert.ToInt32(s[i]) - 48) * (int)Math.Pow(2, pow++);
  13. }
  14. return number;
  15. }





原文地址:https://www.cnblogs.com/xiejunzhao/p/1a4433ae154717102e168b733584ae47.html