Top 10 Coding Interview Questions

Here’s a list of Top 10 Coding Interview Questions for your Programming interviews. These are designed to intrigue viewers of varying expertise levels

Top 10 Coding Interview Questions

1️⃣ Which data structure is best suited for implementing a browser’s forward and back buttons?
2️⃣ How would you efficiently find the first non-repeating character in a string?
3️⃣ Which sorting algorithm is best for nearly sorted arrays?
4️⃣ What is the time complexity of finding an element in a Binary Search Tree (BST) in the average case?
5️⃣ What problem-solving technique is primarily used in the “Knapsack Problem”?
6️⃣ How do you detect a cycle in a Linked List?
7️⃣ Which of these algorithms does NOT work in O(n log n) time complexity?
8️⃣ What is the key advantage of a Trie (Prefix Tree) over a HashMap for storing strings?
9️⃣ What is the Big-O complexity of adding an element to a HashMap in the best case?
🔟 Bonus Question: What is the output of the following code snippet?

1️⃣ Which data structure is best suited for implementing a browser’s forward and back buttons?

• 🅰️ Stack
• 🅱️ Queue
• 🅾️ Linked List
• 🔄 HashMap

Correct Answer: Stack

2️⃣ How would you efficiently find the first non-repeating character in a string?

• 🅰️ Using a HashMap to count frequencies.
• 🅱️ Sorting the string first.
• 🅾️ Iterating through the string twice.
• 🔄 Using a Queue for character traversal.

Correct Answer: 🅰️ Using a HashMap to count frequencies.

3️⃣ Which sorting algorithm is best for nearly sorted arrays?

• 🅰️ Quick Sort
• 🅱️ Merge Sort
• 🅾️ Insertion Sort
• 🔄 Heap Sort

Correct Answer: 🅾️ Insertion Sort

4️⃣ What is the time complexity of finding an element in a Binary Search Tree (BST) in the average case?

• 🅰️ O(1)
• 🅱️ O(log n)
• 🅾️ O(n)
• 🔄 O(n log n)

Correct Answer: 🅱️ O(log n)

5️⃣ What problem-solving technique is primarily used in the “Knapsack Problem”?

• 🅰️ Greedy Algorithm
• 🅱️ Divide and Conquer
• 🅾️ Dynamic Programming
• 🔄 Backtracking

Correct Answer: 🅾️ Dynamic Programming

6️⃣ How do you detect a cycle in a Linked List?

• 🅰️ Using two pointers (slow and fast).
• 🅱️ Using a HashSet to store visited nodes.
• 🅾️ Iterating through the list multiple times.
• 🔄 Both 🅰️ and 🅱️.

Correct Answer: 🔄 Both 🅰️ and 🅱️.

7️⃣ Which of these algorithms does NOT work in O(n log n) time complexity?

• 🅰️ Merge Sort
• 🅱️ Heap Sort
• 🅾️ Quick Sort
• 🔄 Bubble Sort

Correct Answer: 🔄 Bubble Sort

8️⃣ What is the key advantage of a Trie (Prefix Tree) over a HashMap for storing strings?

• 🅰️ Faster search for exact strings.
• 🅱️ Space efficiency for long strings.
• 🅾️ Fast prefix-based searches.
• 🔄 Easier to implement.

Correct Answer: 🅾️ Fast prefix-based searches.

9️⃣ What is the Big-O complexity of adding an element to a HashMap in the best case?

• 🅰️ O(1)
• 🅱️ O(log n)
• 🅾️ O(n)
• 🔄 O(n log n)

Correct Answer: 🅰️ O(1)

🔟 Bonus Question: What is the output of the following code snippet?

int[] nums = {1, 2, 3, 4};
System.out.println(nums[nums.length]);

• 🅰️ 4
• 🅱️ 0
• 🅾️ ArrayIndexOutOfBoundsException
• 🔄 None of the above

Correct Answer: 🅾️ ArrayIndexOutOfBoundsException

These questions are a mix of theoretical and practical coding challenges, ideal for engaging your YouTube audience. Let me know if you’d like to expand on any of these or customize further!