Question

1009. Complement of Base 10 Integer

中文文档

Description

The complement of an integer is the integer you get when you flip all the 0's to 1's and all the 1's to 0's in its binary representation.

• For example, The integer 5 is "101" in binary and its complement is "010" which is the integer 2.

Given an integer n, return _its complement_.

 

Example 1:

Input: n = 5
Output: 2
Explanation: 5 is "101" in binary, with complement "010" in binary, which is 2 in base-10.

Example 2:

Input: n = 7
Output: 0
Explanation: 7 is "111" in binary, with complement "000" in binary, which is 0 in base-10.

Example 3:

Input: n = 10
Output: 5
Explanation: 10 is "1010" in binary, with complement "0101" in binary, which is 5 in base-10.

 

Constraints:

• 0 <= n < 109

 

Note: This question is the same as 476: https://leetcode.com/problems/number-complement/

Solutions

Solution 1

class Solution:
  def bitwiseComplement(self, n: int) -> int:
    if n == 0:
      return 1
    ans = 0
    find = False
    for i in range(30, -1, -1):
      b = n & (1 << i)
      if not find and b == 0:
        continue
      find = True
      if b == 0:
        ans |= 1 << i
    return ans

class Solution {
  public int bitwiseComplement(int n) {
    if (n == 0) {
      return 1;
    }
    int ans = 0;
    boolean find = false;
    for (int i = 30; i >= 0; --i) {
      int b = n & (1 << i);
      if (!find && b == 0) {
        continue;
      }
      find = true;
      if (b == 0) {
        ans |= (1 << i);
      }
    }
    return ans;
  }
}

class Solution {
public:
  int bitwiseComplement(int n) {
    if (n == 0) return 1;
    int ans = 0;
    bool find = false;
    for (int i = 30; i >= 0; --i) {
      int b = n & (1 << i);
      if (!find && b == 0) continue;
      find = true;
      if (b == 0) ans |= (1 << i);
    }
    return ans;
  }
};

func bitwiseComplement(n int) int {
  if n == 0 {
    return 1
  }
  ans := 0
  find := false
  for i := 30; i >= 0; i-- {
    b := n & (1 << i)
    if !find && b == 0 {
      continue
    }
    find = true
    if b == 0 {
      ans |= (1 << i)
    }
  }
  return ans
}