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

# What is the decimal number system?

Long ago, humans created a number system that has exactly ten digits.

This number system is called the **Decimal Number System** and the digits in this number system are **0 1 2 3 4 5 6 7 8 9.**

If a number system has **n** digits, we say that the base of the number system is n. So, the decimal number system can also be called a `base-10` number system.

Let's look at place values for decimals in the below picture.

We write the number in one **row** and multiple **columns**. The rightmost column corresponding to the rightmost digit is called the one's place. The second right column is called the tens place, and we go on increasing in multiples of tens, e.g., hundreds place, thousands place, and so on.

Suppose we have to represent this in powers of 10. In that case, the rightmost place (or the least significant digit) corresponds to $10^{0}$ and continues $10^{1}$ and so on towards the left side.

## Decimal Number System Example

Let's write the number **1256** in the decimal number system.

`int n = 1256;`

Repeatedly do the modulo operation until `n` becomes `0` using:
> "`%`"  and "`division`" operations.



| n (value)|n|n/10 (Quotient)|n%10 (Remainder)|
|-|-|-|-|
| `n` is 1256|1256|125   |  6 |
| `n/10` becomes 125|125|12   |  5 |
| `n/10` becomes 12|  12 | 1  | 2  |
| `n/10` becomes 1| 1  |  0 |  1 |

The decimal number system is the standard system for denoting integer and non-integer numbers.

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

Decimal Number System