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Find Complement of a Number

This README explains how to find the complement of a given number across various programming languages. Each step in the code is broken down to help you understand the underlying logic.

C++ Implementation

Step-by-Step Explanation

  1. Initialize the Mask:

    • A variable mask is initialized to 0. This will eventually represent a bitmask where all bits are set to 1, corresponding to the binary length of the input number num.

  2. Copy the Input Number:

    • Create a temporary variable temp initialized with the value of num. This is used to determine the binary length of num.

  3. Generate the Bitmask:

    • The loop runs while temp is not 0. In each iteration:
      • Shift the current bits in mask to the left by 1 position to make room for the new bit.
      • Set the least significant bit of mask to 1.
      • Right shift temp by 1 to move to the next bit in the binary representation.

  4. Compute the Complement:

    • Use XOR between num and mask to flip all bits of num, producing its complement.

Java Implementation

Step-by-Step Explanation

  1. Initialize the Mask:

    • A variable mask is initialized to 0, which will be used to create a bitmask where all bits are set to 1.

  2. Create a Temporary Copy:

    • Copy the input number num into a temporary variable temp to determine the number of bits in num.

  3. Create the Bitmask:

    • Loop until temp becomes 0:
      • Left shift mask by 1 to make space for the new bit.
      • OR the mask with 1 to set the least significant bit to 1.
      • Right shift temp by 1 to move to the next bit.

  4. Find the Complement:

    • XOR num with the mask to flip all bits and get the complement.

JavaScript Implementation

Step-by-Step Explanation

  1. Initialize the Mask:

    • The mask is initialized to 0. It will eventually have all bits set to 1 within the range of num.

  2. Create a Temporary Variable:

    • Store the value of num in a temporary variable temp for manipulation.

  3. Create the Bitmask:

    • Loop until temp is 0:
      • Shift mask to the left by 1 and set the least significant bit to 1.
      • Right shift temp by 1 to move to the next bit.

  4. Calculate the Complement:

    • XOR num with the mask to flip all bits, effectively finding the complement.

Python Implementation

Step-by-Step Explanation

  1. Initialize the Mask:

    • A variable mask is initialized to 0. This mask will create a number with all bits set to 1, matching the length of num's binary representation.

  2. Temporary Variable Setup:

    • Initialize temp to num to help determine the binary length of num.

  3. Generate the Mask:

    • While temp is not 0:
      • Left shift mask by 1 to make space for the next bit and set the last bit to 1.
      • Right shift temp by 1 to move to the next bit.

  4. Find the Complement:

    • XOR num with mask to flip all bits and compute the complement.

Go Implementation

Step-by-Step Explanation

  1. Initialize the Mask:

    • The mask is initialized to 0. It will be used to cover all the bits of num.

  2. Create a Temporary Variable:

    • Store num in a temporary variable temp, which will help in determining the bit length of num.

  3. Create the Bitmask:

    • The loop continues while temp is not 0:
      • Shift the mask to the left by 1 bit and set the rightmost bit to 1.
      • Right shift temp by 1 bit to reduce its length.

  4. Compute the Complement:

    • XOR num with mask to flip all bits and find the complement.