Contest Experiences | AtCoder Regular Contest 166

Atcoder is a platform where coding enthusiast come to enhance their skills and also participate in contests to gain confidence. On their platform, different types of contests are available such as AHC (AtCoder Heuristic Contest), AGC (AtCoder Grand Contest), ARC (AtCoder Regular Contest), and ABC(AtCoder Beginner Contest).

About the Contest:

• Contest Date: 08/Oct/2023.
• Contest Time: 05:30 pm (IST)
• Duration: 120 minutes
• Number of Questions: 6
• Question-wise point values: 400-400-600-600-800-1100
• Contest Rule: you get a score assigned to it.
• Rank Computed: From the total marks of Question- [(the time you spend to get your current score) + (5 minutes) * (the number of incorrect attempts)].

Contest Link: https://atcoder.jp/contests/arc166

Overview of the Challenge:

Problem Name	Difficulty	Pre-Requisite	Approx. Time to solve
Replace C or Swap AB	Easy	Replace characters	5 min
Make Multiples	Easy	Set	5-7 min
LU / RD Marking	Medium	Grid Dynamic Programming	10 min
Interval Counts	Medium	Segment Tree	20 min
Fizz Buzz Difference	Medium	Basic Mathematics	15 min
Tangent Addition Formula	Hard	modular arithmetic	30 min

Problem 1: Replace C or Swap AB

In this question, Given a String you need to replace the string every occurrence of ‘C‘ with either ‘A‘ or ‘B‘. and if you encounter ‘AB‘ in the given string then reverse it to ‘BA‘.

Problem 2: Make Multiples

Given an array of integers and some ‘a‘, ‘b‘, and ‘c‘ digits, you need to increment the array element by ‘1‘ such that ‘a‘, ‘b‘, and ‘c‘ will divide at least one element of the array.

Problem 3: LU / RD Marking

Given, a grid we need to mark the left and upper edges if they are unmarked or the right and lower edges if they are unmarked. The question asks you to print the number of edges that can be marked

Problem 4: Interval Counts

For this question, you must know the concept of Segment Tree. In this, you need to find out the maximum value of an equation based on a given set of conditions.

Problem 5: Fizz Buzz Difference

This question asks you to find the good pair among a set of positive integers, A good pair stands for, the number of multiples between the sum of integers, and the subtraction of integers is equal to n.

Problem 6: Tangent Addition Formula

This question is a bit tricky, you need to print yes if a non-negative integer series follows certain criteria. Understanding the Criteria is tricky in this question.