Modena

Alternating Characters

patterns  strings 

Anagram

sort  strings 

Angry Professor

patterns 

Append and Delete

strings  math 

Array Manipulation

prefix sum  patterns 

Arron Maximum Profit

prefix sum  patterns 

Balanced Brackets

stack 

Beautiful Binary String

strings 

Beautiful Pairs

frequency table  sort 

Beautiful Triplets

binary search  frequency table  manifold 

Big Sorting

sort 

Bigger is Greater

sort  strings 

Birthday Chocolate

prefix sum  patterns 

Bot Saves Princess

ad hoc  design 

Bus Trip

array  prefix-sum  math 

CamelCase

patterns 

Candies

greedy 

Cavity Map

ad hoc 

Check Sudoku

ad hoc  frequency table  design 

Circular Array Rotation

math 

Climbing the Leaderboard

binary search  sorted sequence 

Closest Numbers

pattern  sort 

Compare the Triplets

patterns 

Counting Valleys

patterns 

Cut the sticks

sort  frequency table 

Cycle Detection

linked lists 

Day of the Programmer

design  ad-hoc 

Designer Pdf Viewer

patterns 

Discard deck

stack  design 

Distracted Shopkeeper

sort  design  binary search 

Electronics Shop

2 pointers  sorting 

Equal Stacks

prefix sum 

eTonno influencers accuracy

subarray  patterns 

Evaluate Expression

design  stack 

Exam Plan

sort  prefix sum  priority queue 

Fair Rations

math  ad hoc 

Fast Maximum

binary search  constrained 

Find Kth Zero

binary search 

Find Maximum Index Product

stack 

Find the Maximum Difference

patterns  prefix sum  2 pointers 

Find the Missing Value

manifold  frequency-table  math 

Find the Running Median

priority queue 

Fixed Adjacent Values

ad hoc 

Flatland Space Stations

prefix sum 

Fraudulent Activity Notifications

frequency-table  priority-queue 

Frequency Queries

hashtable  frequency-table 

Game of Thrones

frequency table 

Gaming Array

prefix-sum  patterns  games 

Gap Up and Down

patterns 

Gemstones

hashtable  frequency table 

Greedy Florist

sort  patterns 

Happy Ladybugs

strings  frequency table 

Herb and Bjarne

math 

Hidden unique integers

strings  patterns 

Hotel Coverage

sort  ad hoc  greedy 

Ice Cream Parlor

sort  frequency table  2-pointers 

Impress the Interviewer

binary search  constrained 

Jesse and Cookies

priority queue 

Jim and the Orders

patterns  sort 

Left Rotation

patterns 

Leonardo's Apprentice

string  patterns 

Lily's Homework

sort 

Luck Balance

sort 

Making Anagrams

strings  frequency table 

Marc's Cakewalk

patterns  sort  prefix-sum 

Mark and Toys

sort 

Mars Exploration

patterns 

Max Min

patterns  sort  functional 

Maximum Perimeter Triangle

greedy  math 

Mini-Max Sum

sort  prefix sum 

Minimum Absolute Difference in an Array

patterns  sort  functional 

Minimum Distances

hashtable 

Minimum Index Distance

ad hoc 

Minimum Loss

binary search  patterns  sort 

Most Distant

math 

New Year Chaos

ad hoc  sorted sequence  constrained 

Number of Subordinates

binary search  sort  prefix sum 

Odd or Even Sum

prefix sum 

One Swap

patterns  ad-hoc 

Padel tournament

2-pointers  sorting 

Pair picker

frequency-table  hashtable 

Pairs

sorting  hashtable  binary-search 

Palindrome Index

patterns  strings 

Party coolness

stack 

Permuting Two Arrays

patterns  sort 

Picking Numbers

sort  frequency table  prefix sum 

Poker hand

frequency table  design 

Positive or Negative

sorted sequence  binary search 

Product of Array Except Self

math  constrained  prefix sum 

Queue Using Two Stacks

constrained  stack 

Raid planner

graphs 

Reckless drivers

patterns  intervals 

Repeated String

strings 

Restaurant

math 

Roman Number

binary search 

Running routes

sort  manifold  prefix-sum  intervals 

Sam and substrings

dynamic-programming  prefix-sum 

Secret repetition

frequency table  math 

Server energy balancing

2-pointers  binary-search  math 

Sherlock and Array

prefix sum  manifold  2 pointers 

Sherlock and Pairs

frequency table 

Sherlock and Squares

math 

Sherlock and the Valid String

frequency table 

Simple Text Editor

stack 

Simplify Path

stack 

Smallest Rearrangement Spell

frequency table 

Spiral line

matrices  ad-hoc 

Squares of a Sorted Array

2 pointers  sort  constrained 

Staircase

strings 

Stock Maximize

prefix sum  patterns 

Streaming quality

prefix-sum  design 

String Construction

sort  frequency-table 

Strong Password

manifold  bitset  design 

Student Sections

binary search  prefix sum  manifold 

Students arrangement

sort  ad-hoc 

Super Reduced String

strings 

Tasty Meal

string  prefix sum 

The Absent Students

sort  manifold 

The Crazy Broker

prefix sum  preprocessing  binary search 

The Forgotten Meeting

binary search  intervals 

The Love-Letter Mystery

patterns 

The Lucky Employee

frequency table  prefix sum  hashtable 

The Master of Cryptocurrencies

patterns 

The maximum subarray

dynamic programming  prefix sum 

The Most Frequent

frequency table  hashtable 

The Next Greater Element

stack 

The Product Name

strings  frequency-table 

The Salesman in a Rush

math 

The Versioned Scroll

binary-search  design 

Triple Sum

sorting  binary search 

Two peaks

greedy  2-pointers 

Valid schedule

intervals 

Weighted Uniform String

sort  binary search