Today, I tackled two foundational and frequently asked coding interview problems — Two Sum and Palindrome Number — both great for strengthening your problem-solving skills in JavaScript. I focused on writing clean code, understanding constraints, dry running inputs, and thinking through edge cases.

✅ Problem 1: Two Sum

📝 Problem Statement:

• Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target.

• You may assume that each input would have exactly one solution, and you may not use the same element twice.

• Return the answer in any order.

Example

Input: nums = [2, 7, 11, 15], target = 9 Output: [0, 1] // Explanation: Because nums[0] + nums[1] == 9 

✅ JavaScript Code:

 var twoSum = function(nums, target) { if(nums.length < 2) return null; for(let i = 0; i < nums.length; i++) { for(let j = i + 1; j < nums.length; j++) { if(nums[i] + nums[j] === target) { return [i, j]; } } } }; // Testing the function console.log('First Answer', twoSum([2, 7, 11, 15], 9)); // [0,1] console.log('Second Answer', twoSum([3, 2, 4], 6)); // [1,2] console.log('Third Answer', twoSum([3, 3], 6)); // [0,1] console.log('Fourth Answer', twoSum([3, 2, 3], 6)); // [0,2] 

✅ Problem 2: Palindrome Number

📝 Problem Statement:

• Given an integer x, return true if x is a palindrome, and false otherwise.

Example

 Input: x = 121 Output: true Input: x = -121 Output: false Input: x = 10 Output: false 

✅ JavaScript Code:

 var isPalindrome = function(x) { let ActualValue = x.toString(); let ReverseValue = x.toString().split('').reverse().join(''); console.log(ActualValue, ReverseValue); return ActualValue === ReverseValue; }; // Testing the function console.log(isPalindrome(121)); // true console.log(isPalindrome(-121)); // false console.log(isPalindrome(10)); // false 

🔁 What I Learned Today

🧠 1. Dry Run Is Powerful

Manually walking through the logic before coding saved time and reduced bugs.

🧩 2. Think About Edge Cases

I considered inputs like:

• Arrays with one element
• Duplicate values
• Negative integers

🧼 3. Clean Code Matters

Writing clean and readable code helps future-proof my logic and reduces confusion.

⚙️ 4. Brute Force is OK at First

Start with what's simple and correct. Optimization can come later once the logic is solid.

✍️ 5. "Copy & Think" Habit

Instead of copy-pasting code, I pause to understand why it works. This makes learning deeper and longer-lasting.