The ultimate guide to coding interviews. Developed by FAANG engineers. Boost problem-solving skills with number theory, dynamic programming, and graph theory. Get interview-ready in just a few hours.

Competitive Programming - Crack Your Coding Interview.png

Whether you’re gearing up for online coding challenges, code-a-thons, or interviews, then this course is for you. With this course, you will solidify your problem-solving skills ensuring a swift sail through any problem. 


You will be tasked with solving some of the most frequently asked questions that are brought up in FAANG interviews. You will start with the concepts of Number Theory and Divide and Conquer, and gradually move towards more complex problems like dynamic programming and graph theory.


With each problem you solve, there will be insightful explanations and full implementation details to really hammer home the concepts. By the time you finish this course, you will have the confidence to solve any problem, no matter the difficulty.

Competitive Programming - Crack Your Coding Interview, C++

# Problem statement
**You are given a list of numbers in which every number is occurring twice except for one number. Find out the unique number.**

# Solution: `Bit-masking approach`

For this problem, we can use the logical **XOR** operation.
>  For two given logical statements, the **XOR** function would return **TRUE** if one of the statements is true and **FALSE** if both statements are true. If neither of the statements is true, it returns **FALSE** again.

Let's look at the following example:

We have two numbers, **a = 10** and **b = 10**. The bit representation will be **1010**. When we perform **XOR** of these two numbers, we get **0**.

The same approach we can use to solve this problem. We will perform the **XOR** operation on all the elements present in the list. At last, the result from **XOR** will be that unique number.

Let's look at the implementation now.

Solve a problem based on bit-masking to find a unique number.

Overview

Number Theory

Number Theory

Divide and Conquer

Greedy Algorithms

Greedy Algorithms

Recursion and Backtracking

Recursion and Backtracking

Dynamic Programming

Graphs

Bonus Lessons

Find the Unique Number

Problem statement