LeetCode 136: Single Number | JavaScript Solution Using Hash Table

🚀 In this video, we solve LeetCode Problem 136: Single Number using a Hash Table approach!
Learn how to efficiently find the unique number in an array where every other element appears twice. This beginner-friendly tutorial walks you through a step-by-step explanation of using a hash table to count occurrences and identify the single number.
📝 Problem Statement:
Given a non-empty array of integers nums, where every element appears twice except for one, return that single number.
Constraints:
✅ Must run in O(n) time complexity
✅ Should use O(1) or minimal extra space
💡 What You’ll Learn:
✅ How to use a hash table (JavaScript object) to store frequency counts
✅ How .includes(), .splice(), and .indexOf() help find duplicates
✅ Time complexity considerations and alternative approaches
🔍 Solution Highlights:
✅ Iterate through nums and store counts in a hash table
✅ If a number appears twice, remove it; otherwise, store it
✅ Return the number that appears only once
📋 Examples in the Video:
🔹 Example 1:
Input: [2,2,1]
Output: 1
🔹 Example 2:
Input: [4,1,2,1,2]
Output: 4
🔹 Example 3:
Input: [1]
Output: 1
🚀 Why Watch?
🎯 Great for coding interviews and JavaScript problem-solving practice
🎯 Understand how hash tables efficiently track counts
🎯 Learn about time complexity trade-offs between different approaches
🔗 Resources:
🔹 LeetCode Problem Link : leetcode.com/p...
🔹 [Code in the Video](leetcode.com/p...)
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