求整数的补码 |设置 2

给定一个整数N ，找到整数的反码。

例子：

Input: N = 5
Output: 2
Explanation: Binary representation of 5 is “101”. Its one’s complement is “010” = 2.

Input: N = 255
Output: 0

Input: N = 26
Output: 5

方法：文章的 Set-1 中已经提到了基于 XOR 的方法和将数字转换为二进制数的方法。在这里，数字是通过翻转位并将 2 的幂添加到答案来转换的。按照下面提到的步骤来实现它：

• 求 N 的二进制表示。
• 对于每个位，对其进行补充并将该位的贡献添加到最终答案中。
• 返回最终答案

下面是上述方法的实现。

C++

// CPP program to find 1's complement of N.
#include 
using namespace std;
 
// Find the 1's complement of N
int findComplement(int num)
{
    int ans = 0;
    for (int i = 0; num > 0; i++) {
        ans += pow(2, i) * (!(num % 2));
        num /= 2;
    }
 
    return ans;
}
 
// Driver code
int main()
{
    unsigned int N = 5;
    cout << findComplement(N);
    return 0;
}

Java

// Java code for the above approach
import java.util.*;
public class GFG
{
 
  // Find the 1's complement of N
  static int findComplement(int num)
  {
    int ans = 0;
    for (int i = 0; num > 0; i++) {
      if(num % 2 == 0) {
        ans += (int)Math.pow(2, i) ;
      }
      num /= 2;
    }
 
    return ans;
  }
 
  // Driver code
  public static void main(String args[])
  {
    Integer N = 5;
    System.out.println(findComplement((int)N));
  }
}
 
// This code is contributed by Samim Hossain Mondal

Python3

# python3 program to find 1's complement of N.
 
# Find the 1's complement of N
def findComplement(num):
 
    ans = 0
    i = 0
    while(True):
        if num == 0:
            break
        ans += pow(2, i) * (not (num % 2))
        num //= 2
        i += 1
 
    return ans
 
# Driver code
if __name__ == "__main__":
 
    N = 5
    print(findComplement(N))
 
# This code is contributed by rakeshsahni

C#

// C# code for the above approach
using System;
class GFG
{
   
// Find the 1's complement of N
static int findComplement(int num)
{
    int ans = 0;
    for (int i = 0; num > 0; i++) {
        if(num % 2 == 0) {
            ans += (int)Math.Pow(2, i) ;
        }
        num /= 2;
    }
 
    return ans;
}
 
// Driver code
public static void Main()
{
    uint N = 5;
    Console.Write(findComplement((int)N));
}
}
 
// This code is contributed by Samim Hossain Mondal

Javascript

      // JavaScript code for the above approach
 
 
      // Find the 1's complement of N
      function findComplement(num) {
          let ans = 0;
          for (let i = 0; num > 0; i++) {
              ans += Math.pow(2, i) * (!(num % 2));
              num = Math.floor(num / 2);
          }
 
          return ans;
      }
 
      // Driver code
 
      let N = 5;
      document.write(findComplement(N));
 
 
// This code is contributed by Potta Lokesh
  

输出

2

时间复杂度： O(log N)
辅助空间： O(1)