Find the Only Non Repeating Element Using XOR in DSA Python - Build from Scratch

Find the Only Non Repeating Element Using XOR

📖 Scenario: Imagine you have a list of numbers where every number appears twice except for one number that appears only once. You want to find that unique number quickly.

🎯 Goal: Build a small program that finds the only number that does not repeat in a list using the XOR operation.

📋 What You'll Learn

Create a list called numbers with the exact values: [2, 3, 5, 4, 5, 3, 4]

Create a variable called unique and set it to 0

Use a for loop with variable num to iterate over numbers and update unique by XORing it with num

Print the value of unique to show the only non-repeating element

💡 Why This Matters

🌍 Real World

Finding unique elements quickly is useful in error detection, data cleaning, and network packet analysis.

💼 Career

Understanding bitwise operations and efficient algorithms is important for software developers and data engineers.

1

Create the list of numbers

Create a list called numbers with these exact values: [2, 3, 5, 4, 5, 3, 4]

DSA Python

# Create the list called numbers with the given values
# Your code here

Hint

Use square brackets [] to create the list and separate numbers with commas.

2

Initialize the variable to hold the unique number

Create a variable called unique and set it to 0

DSA Python

numbers = [2, 3, 5, 4, 5, 3, 4]
# Create a variable called unique and set it to 0
# Your code here

Hint

Set unique to zero because XOR with zero returns the other number unchanged.

3

Use XOR in a loop to find the unique number

Use a for loop with variable num to iterate over numbers and update unique by XORing it with num inside the loop

DSA Python

numbers = [2, 3, 5, 4, 5, 3, 4]
unique = 0
# Use a for loop to XOR each number with unique
# Your code here

Hint

Use ^= to XOR and update unique in each loop step.

4

Print the unique number

Print the value of unique to show the only non-repeating element

DSA Python

numbers = [2, 3, 5, 4, 5, 3, 4]
unique = 0
for num in numbers:
    unique ^= num
# Print the unique number
# Your code here

Hint

The printed number is the one that appears only once in the list.