Leetcode with dani

🎯 Problem of the Day: Sort Colors

Problem Description
You are given an array nums with \( n \) objects colored red, white, or blue. Sort the array in-place so that objects of the same color are adjacent, with the colors in the order red, white, and blue.
- Represent the colors using integers:
- 0 → Red
- 1 → White
- 2 → Blue

⚠️ Note: You must not use the library's sort function.

---

Example 1
Input:

nums = [2,0,2,1,1,0]

Output:

[0,0,1,1,2,2]

Example 2
Input:

nums = [2,0,1]

Output:

[0,1,2]

---

📝 Practice Questions for A2SV Preparation
1. Core Problem:
- Solve LeetCode 75: Sort Colors () using Dutch National Flag Algorithm for \( O(n) \) time complexity.

2. Related Problems:
- LeetCode 215 : Kth Largest Element in an Array
- LeetCode 347 : Top K Frequent Elements
- LeetCode 56 : Merge Intervals

3. Challenge Problem:
- LeetCode 88: Merge Sorted Array

---

💡 Tip: Use a two-pointer or three-pointer approach to keep track of boundaries for the different colors! Try to optimize your solution to \( O(n) \) in both time and space.

🧠 Share your solution and discuss your approach with the community! 🌟

Hello G6 In-Person Education Applicants,

As you gear up for your interviews, we want to inform you about the key topics to focus on. These are the areas that will be covered during the interview:

- Sorting
- Two Pointers
- Sliding Window
- Prefix Sum
- Stacks and Queues

Best of luck with your preparation! Stay confident and ready to showcase your skills.

ወንድማችን ተማሪ አዲሱ አገዘ የአ.አ.ዩ /CNCS የChemistry ዲፓርትመንት ተማሪ ሲሆን በድንገተኛ የጤና እክል ምክንያት በጥቁር አንበሳ ስፔሻላይዝድ ሆስፒታል የህክምና ክትትል እየተደረገለት ይገኛል። ሆኖም ግን ለህክምናና ለአንዳንድ ወጪዎች የሚሆነውን ገንዘብ መሸፈን ስላልተቻለ ለእርዳታ ሲባል ባለ3 ጥምር የባንክ አካውንት ተከፍቶ አቅም የፈቀደውን እና ልብ የወደደውን ገቢ በማድረግ የእርዳታ እጃችሁን እንድትዘረጉልን ስንል በፈጣሪ ስም እንጠይቃለን።

ድር ቢያብር...

1000660602899 Surafel and Lud and Belete (CBE)

ለመረጃ: 0928750009

FOR A2SV

Applications are Open for A2SV G6 Education!

The time has come for A2SV to welcome new members! We’re looking for team-oriented individuals with a never-give-up mentality, ready to drive tech excellence and solve impactful challenges.

📅 Application opens: November 14, 2024
📅 Deadline: November 20, 2024, at 11:59 PM EAT

🎓 Eligibility

Open to current students from Addis Ababa University (AAU), Addis Ababa Science and Technology University (AASTU), and Adama Science and Technology University (ASTU). If you're not from these schools or have already graduated, stay tuned for future remote applications!

🔍 Requirements

- Familiarity with at least one programming language
- Experience with platforms like LeetCode or Codeforces
- Completed at least 40 problems on LeetCode or Codeforces

🤖 Selection Process

- First Round Filtering: Initial application review
- Technical & Behavioral Interviews: For selected candidates, to assess skills and fit for the program

⌛️ Don’t wait! Start your application early to ensure a standout submission. 🎯

🔗 Apply now: link

#A2SV #TechEducation #EmpoweringAfrica #ApplyNow

So, the prime numbers are the unmarked ones: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89 and 97.

We continue this process, and our final table will look like below:

We move to our next unmarked number 5 and mark all multiples of 5 and are greater than or equal to the square of it.

Now we move to our next unmarked number 3 and mark all the numbers which are multiples of 3 and are greater than or equal to the square of it.

According to the algorithm we will mark all the numbers which are divisible by 2 and are greater than or equal to the square of it.

Let us take an example when n = 100. So, we need to print all prime numbers smaller than or equal to 100.


We create a list of all numbers from 2 to 100.

Sieve of Eratosthenes

Given a number n, print all primes smaller than or equal to n. It is also given that n is a small number.

Example:

Input : n =10
Output : 2 3 5 7


Input : n = 20
Output: 2 3 5 7 11 13 17 19

The sieve of Eratosthenes is one of the most efficient ways to find all primes smaller than n when n is smaller than 10 million or so.

Following is the algorithm to find all the prime numbers less than or equal to a given integer n by the Eratosthene’s method:
When the algorithm terminates, all the numbers in the list that are not marked are prime.

Explanation with Example:

Given a number n, print all primes smaller than or equal to n. It is also given that n is a small number.

Example:

Input : n =10
Output : 2 3 5 7


Input : n = 20
Output: 2 3 5 7 11 13 17 19

share ur answer in the comment section , i will check it

🏆 LeetCode 490. The Maze (Premium) 🏆

There's a ball in a maze with:
- Empty spaces (0) and walls (1).

The ball can roll in any direction:
- Up, down, left, or right 🌐

But here's the catch:
- It won't stop until it hits a wall! 🚧
- Once it stops, it can choose another direction to roll.

### Task 🎯
Given:
- An m x n maze
- The ball's starting position and a destination

Determine:
- Can the ball stop at the destination?
- If yes, return true. Otherwise, return false.

📝 Assumption: All borders of the maze are walls.

---

### Examples 🔍

Example 1:

Input: 
maze = [
  [0,0,1,0,0], 
  [0,0,0,0,0], 
  [0,0,0,1,0], 
  [1,1,0,1,1], 
  [0,0,0,0,0]
], 
start = [0,4], 
destination = [4,4]

Output: true

Explanation: One possible path: left ➡️ down ➡️ left ➡️ down ➡️ right ➡️ down ➡️ right 🎯

---

Example 2:

Input:
maze = [
  [0,0,1,0,0], 
  [0,0,0,0,0], 
  [0,0,0,1,0], 
  [1,1,0,1,1], 
  [0,0,0,0,0]
], 
start = [0,4], 
destination = [3,2]

Output: false

Explanation: The ball can pass through the destination, but it cannot stop there. ❌

---

Example 3:

Input:
maze = [
  [0,0,0,0,0], 
  [1,1,0,0,1], 
  [0,0,0,0,0], 
  [0,1,0,0,1], 
  [0,1,0,0,0]
], 
start = [4,3], 
destination = [0,1]

Output: false

---

### Constraints 📏
- Maze Dimensions: 1 ≤ m, n ≤ 100
- Cells contain only 0 (empty) or 1 (wall).
- Start and destination are in empty spaces and won’t initially overlap.

Can you solve it? 🤔

Hello fellow coders,

After a brief break, we've returned! Get ready for our fun weekly community coding contest happening every Saturday 🗓. It's your chance to compete with other awesome programmers, learn more about coding, and, most importantly, have a great time! 🥳

🏆 Contest Details:
📅 Date: November 2, 2024
⏰ Time: 6:00 PM
🔗 Link for Contest: Community Weekly Contest Return - Contest No 1

P.S. Remember to fill out this form to secure your spot for our upcoming community classes and lectures. It’s your golden ticket to enriching experiences you won’t want to miss. 📚✨