Master Atcoder Beginner Contest 202 with Solutions!

Master Atcoder Beginner Contest 202 with Solutions!

Table of Contents

1. Introduction
2. Coder Beginner Contest 202
3. Registering an Ad Coder Account
4. Problem 1: Rolling Three Dice
5. Problem 2: Rotating Numbers in a STRING
6. Problem 3: Counting Pairs in Sequences
7. Problem 4: Finding Lexicographically Sorted String
8. Problem E: Shortest Path Queries in a Tree

Introduction

In this article, we will Delve into the details of the Coder Beginner Contest 202. We will explore the process of participating in the contest and the benefits it offers for beginners. Additionally, we will discuss the importance of registering an Ad Coder account to make the most out of the contest.

Coder Beginner Contest 202

The Coder Beginner Contest 202 is an exciting event for programmers who are just starting. It provides a platform to test and improve their coding skills through a series of challenges. The contest starts with relatively easy questions that gradually increase in difficulty. For beginners, this progressive approach allows them to grasp the fundamentals and build confidence in their abilities.

Registering an Ad Coder Account

Before diving into the contest, it is crucial to register an Ad Coder account. By creating an account, participants gain access to a wide range of coding resources, tutorials, and practice problems. This enables them to enhance their skills and be better prepared for the challenges posed in the Coder Beginner Contest 202.

Problem 1: Rolling Three Dice

The first problem in the contest involves rolling three dice and calculating the sum of the numbers on their bottom surfaces. Participants need to determine the sum by subtracting the numbers on the top surfaces from 21. This straightforward problem serves as a warm-up exercise for the participants.

Problem 2: Rotating Numbers in a String

The Second problem introduces the concept of rotating numbers in a string. The given string consists of only numerical characters. The task is to rotate the string by 180 degrees, replacing 6 with 9 and vice versa. Participants are required to reverse the string and perform the necessary replacements to obtain the final result.

Problem 3: Counting Pairs in Sequences

In the third problem, participants are presented with three sequences consisting of integers. The goal is to determine the number of pairs that satisfy the condition ai = bcj. To solve this, participants must analyze the sequences, replace one of the arrays with the corresponding bcg elements, and calculate the frequency of each element. By comparing the frequencies, they can determine the number of pairs that meet the given condition.

Problem 4: Finding Lexicographically Sorted String

Problem four involves finding a string that comes first in lexicographical order among all possible strings of a given length with a specific number of occurrences of 'a' and 'b'. Participants are required to make decisions Based on whether the count of 'a's allows for the creation of at least k strings. By using combinations and permutations, participants can determine the appropriate characters to put in the string.

Problem E: Shortest Path Queries in a Tree

The final problem of the contest deals with shortest path queries in a tree. Participants are provided with a tree, and for each query, they are given a vertex ui and an integer di. The task is to find the number of vertices at depth di in the subtree of ui. This problem can be approached using techniques such as Euler tours or Sack (Subtree Size for Each Vertex). These techniques involve traversing the tree, storing start and end times, and performing range queries to obtain the desired result.

Conclusion

Participating in the Coder Beginner Contest 202 provides beginners with an opportunity to enhance their coding skills and gain valuable experience. By completing a series of challenges, participants can strengthen their understanding of various programming concepts. Registering an Ad Coder account further complements this learning process, as it grants access to additional resources and practice problems. So why wait? Register for the contest, put your coding skills to the test, and embark on a Journey of continuous growth.

Highlights

• The Coder Beginner Contest 202 is a perfect platform for beginner programmers to enhance their coding skills.
• Registering an Ad Coder account provides access to valuable coding resources and practice problems.
• Problem 1 involves calculating the sum of numbers on the bottom surfaces of three dice.
• Problem 2 requires rotating numbers in a string by 180 degrees.
• Problem 3 focuses on finding pairs that satisfy a specific condition in given sequences.
• Problem 4 involves finding the lexicographically sorted string among all possibilities.
• Problem E deals with shortest path queries in a tree, utilizing techniques like Euler tours or Sack.

FAQ

Q: Can I participate in the Coder Beginner Contest 202 as an intermediate programmer? A: While the contest primarily caters to beginners, intermediate programmers can also participate to test their skills and potentially help others along the way.

Q: How can I register an Ad Coder account? A: To register an Ad Coder account, visit their official website and follow the registration process. It is a simple and straightforward procedure.

Q: Are the challenges in the Coder Beginner Contest 202 suitable for absolute beginners? A: Yes, the initial challenges in the contest are designed to be beginner-friendly, ensuring that participants can grasp the fundamentals and gradually build their skills.

Q: Can I use any programming language for the contest? A: Yes, you are free to choose any programming language that you are comfortable with to solve the contest problems.

Q: How can I approach the shortest path queries problem in the contest? A: There are multiple approaches to solve the shortest path queries problem, such as using Euler tours or Sack. These techniques involve traversing the tree and performing range queries to obtain the desired results.