Modena

Anagram

Append and Delete

Array Left Rotation

Balanced Brackets

stack 

Beautiful Binary String

string 

Beautiful Triplets

binary search  frequency table  manifold 

Big Sorting

sort 

Bot Saves Princess

CamelCase

Cavity Map

ad hoc 

Circular Array Rotation

math 

Climbing the Leaderboard

binary search  sorted sequence 

Closest Numbers

pattern  sort 

Compare the Triplets

Counting Valleys

patterns 

Cycle Detection

Day of the Programmer

design  ad-hoc 

Designer Pdf Viewer

Distracted Shopkeeper

Electronics Shop

2 pointers  sorting 

Equal Stacks

prefix sum 

Evaluate Expression

design  stack 

Fair Rations

math  ad hoc 

Find Kth Zero

binary search 

Find the Maximum Difference

Find the Missing Value

manifold 

Fixed Adjacent Values

ad hoc 

Flatland Space Stations

Game of Thrones

frequency table 

Gap Up and Down

patterns 

Gemstones

hashtable  frequency table 

Greedy Florist

Happy Ladybugs

strings  frequency table 

Herb and Bjarne

Hotel Coverage

sort  ad hoc  greedy 

Impress the Interviewer

binary search  constrained 

Jesse and Cookies

priority queue 

Jim and the Orders

patterns  sort 

Making Anagrams

string  frequency table 

Mark and Toys

sort 

Mars Exploration

patterns 

Min Max

patterns  sort  functional 

Mini-Max Sum

Minimum Absolute Difference in an Array

patterns  sort  functional 

Minimum Distances

hashtable 

Minimum Index Distance

Minimum Loss

binary search  patterns  sort 

New Year Chaos

ad hoc  sorted sequence  constrained 

Number of Subordinates

Odd or Even Sum

One Swap

patterns  ad-hoc 

Pairs

sorting 

Palindrome Index

Permuting Two Arrays

Picking Numbers

sort  frequency table  prefix sum 

Product of Array Except Self

math  constrained  prefix sum 

Queue Using Two Stacks

constrained  stack 

Restaurant

math 

Roman Number

Sherlock and Array

Sherlock and Pairs

frequency table 

Sherlock and Squares

Sherlock and the Valid String

frequency table 

Simple Text Editor

stack 

Simplify Path

stack 

Smallest Rearrangement Spell

Squares of a Sorted Array

2 pointers  sort  constrained 

Staircase

String Construction

sort  frequency-table 

Strong Password

manifold  bitset  design 

Student Sections

binary search  prefix sum  manifold 

Super Reduced String

The Absent Students

sort  manifold 

The Crazy Broker

prefix sum  preprocessing  binary search 

The Love-Letter Mystery

The Lucky Employee

frequency table  prefix sum  hashtable 

The Master of Cryptocurrencies

The Most Frequent

frequency table  hashtable 

The Next Greater Element

stack 

The Salesman in a Rush

The maximum subarray

dynamic programming  prefix sum 

Triple Sum

sorting  binary search 

Weighted Uniform String

sort  binary search