Contest Experiences | AtCoder Regular Contest (ARC) 157

Atcoder is one of the leading Platforms providing different contests for coding enthusiasts. 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: 25/Feb/2023.
• Contest Time: 05:30 pm (IST)
• Duration: 120 minutes
• Number of Questions: 6
• Question-wise point values: 300-500-600-600-700-900
• 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/arc157

Overview of the Challenge:

Problem Name	Difficulty	Pre-Requisite	Approx.Time
XXYYX	Easy	Substring	5 min
XYYYX	Easy	Substring	5-7 min
YY Square	Medium	Binomial Coefficient	10 min
YY Garden	Medium	modulo	10 min
XXYX Binary Tree	Hard	Binary Tree	15 min
XY Ladder LCS	Hard	Common Subsequence	20 min

Problem 1: XXYYX

In this question Given a String you need to check whether there are exact pair of ‘XX’, ‘XY’, ‘YX’ and ‘YY’. if the condition satisfy print Yes otherwise No.

Problem 2: XYYYX

This question is a bit similar to problem 1, Given a string in which you need to convert ‘X’ as ‘Y’ and ‘Y’ as ‘X’ and lastly print the maximum pairs of consecutive ‘Y’.

Problem 3: YY Square

Given a grid having some Row and Column, each cell has either ‘X’ or ‘Y’. You can move in the left and down direction in this grid and find the number of consecutive Y with their binomial coefficient.

Problem 4: YY Garden

There is a Grid of H row and W column. where each cell has either X or Y. You need to set a fence that has exactly two YS written on it. Given, There are 2^H−1 ×2^W−1 ways to set up fences. You need to check how many of them satisfy, modulo 998244353

Problem 5: XXYX Binary Tree

In this question, given a Binary tree, you need to put X and Y in each vertex in such a way that they satisfy the given constraints.

Problem 6: XY Ladder LCS

Given Two strings containing X and Y, you need to swap the character of the string and find the common subsequence of both strings. You have to note after swapping if some common subsequence occurs you need to ignore it.

Conclusion:

This contest is tough and also if you are beginner then don’t give ARC(Atcoder Regular Contest) start with easy question in ABC(Atcoder Beginer Contest). Also, if your goal is only to crack placement then this much won’t be required. But if your goal is to mastering Competative Programming then this platform is for you.