#leet_code_Q1 #Array Given a non-empty array of integers nums, every element appears twice except for one. Find that single one.

You must implement a solution with a linear runtime complexity and use only constant extra space.



Example 1:

Input: nums = [2,2,1]
Output: 1
Example 2:

Input: nums = [4,1,2,1,2]
Output: 4
Example 3:

Input: nums = [1]
Output: 1 Each element in the array appears twice except for one element which appears only once.

#leet_code_Q2 #Array #leet_code_169 #Majority_Element Given an array nums of size n, return the majority element.

The majority element is the element that appears more than (n / 2)times. You may assume that the majority element always exists in the array.

Example 1:

Input: nums = [3,2,3]
Output: 3
Example 2:

Input: nums = [2,2,1,1,1,2,2]
Output: 2

Day 5
🗓 Daily Challenge #1
🧩 Build Array from Permutation
Given an array nums, build a new array ans where ans[i] = nums[nums[i]] for every index i.
Can you solve it without extra space? (Hint: Think modulo!)

🔗 Problem Link:
📌 Difficulty: Easy
🏷 Tags: #Array #InPlace

💡 Let’s see your optimized solutions!
👉 Drop your approach in the comments!

📊 Problem Breakdown #2
🔄 Matrix Rotation Check
Given two n x n matrices, determine if one can be obtained by rotating the other 90°, 180°, or 270°.
How would you efficiently check all possible rotations?

🔗 Problem Link:
📌 Difficulty: Medium
🏷 Tags: #Matrix #Transpose

🤔 Think about transpose + reverse vs. brute force. Which is better?
👉 Share your code snippets!

🚀 Advanced Problem Alert!
🔢 Tuple with Same Product
Find the number of tuples (a, b, c, d) such that a*b = c*d where all elements are distinct.
Can you avoid an O(n⁴) solution? (Hint: Hash maps are your friend!)

🔗 Problem Link:
📌 Difficulty: Medium
🏷 Tags: #HashTable #Combinatorics

💥 Challenge: Optimize for large arrays!
👉 Post your best time complexity in the comments!