The ultimate guide to bit manipulation for coding interviews. Developed by FAANG engineers, practice with real-world interview questions, and get interview-ready in just a few hours.

This course teaches bit manipulation, a powerful technique to enhance algorithmic and problem-solving skills. It is a critical topic for those preparing for coding interviews for top tech companies, startups and industry leaders. Competitive programmers can take full advantage of this course by running most of the bit-related problems in O(1) complexity.

The course will begin by educating you about the number system and its representation, decimal and binary, followed by the six bitwise operators: AND, OR, NOT, XOR, and bit-shifting (left, right).

You will receive ample practical experience working through practice problems to improve your comprehension.

Upon completing this course, you will be able to solve problems with greater efficiency and speed.

Grokking Bit Manipulation for Coding Interviews

# Introduction

In this question, we will flip the bits to make two numbers equal to the third number.

Let's see how to achieve this using the **OR** operator.

# Problem statement
We need to write a program with minimum flips to make the two bits' OR operation equal a number.

```
Input: a = 2, b = 6, c = 5
 
Output: 3
```

Explanation: After flips, a = 1 , b = 4 , c = 5 such that (a OR b == c).

> Assume `n` is non-negative.
Use the `|` operator to achieve this.

# Solution

We have three positives numbers, `a`, `b`, and `c`. We have to find the minimum flips required in some bits of a, b to make (a `OR` (b == c)). Here we are considering Bitwise OR operation. The flip operation consists of changing any single bit 1 to 0 or changing the bit 0 to 1 in their binary representation. 

> If, `a = 0010` and `b = 0110`, so `c = 0101`;

After flips, `a` will be `0001`, and `b` will be `0100`.


**Algorithm:**

* Initialize `ans` variable to `0`.
* Loop through, in the range from 0 to 31
  * Initialize 
    * `bitA` = ($\frac{a}{2^{i}}$) & 1
    * `bitB` = ($\frac{b}{2^{i}}$) & 1
    * `bitC` = ($\frac{c}{2^{i}}$) & 1
  * If ( `bitA | bitB` ) is not same as `bitC`, then
     * If `bitC` is `0`
       * If `bitA = 1` and `bitB = 1`, then  increase ans by 2, otherwise        
        * Increase `ans` by 1, 
     * Increase `ans` by 1
* Return `ans`

## Code

If you understand the OR operations clearly, then this problem will be a good challenge for your skills. Make sure you have a clear understanding of OR before moving on.

Getting Started

Number Systems, Bitwise, and Binary

Bitwise AND

Bitwise OR

Bitwise NOT

Bitwise XOR

Bit Shifting - Left, Right

Bitwise LeftShift Problems

Bitwise RightShift Problems

Final Thoughts

Number Of Flips Required To Make a|b Equal to c

Introduction

Problem statement

Solution