# The collection of Scala algorithms

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## 100 Scala Algorithms

#1Balanced parentheses algorithm with tail-call recursion

#### Free

#2Check if an array is a palindrome

#### Free

#3Find an unpaired number in an array

#### Free

#4Count binary gap size of a number using tail recursion

#### Free

#5Find maximum potential profit from an array of stock price

#### Free

#6Fizz Buzz in purely functional immutable Scala

#### Free

#7Binary heap (min-heap)

#### Free test cases & hints

#8Compute missing ranges

#### Free test cases & hints

#9Find kth largest element in a List

#### Free test cases & hints

#10Find the minimum item in a rotated sorted array

#### Free test cases & hints

#11Compute the steps to transform an anagram only using swaps

#### Free test cases & hints

#12Compute minimum number of Fibonacci numbers to reach sum

#### Free test cases & hints

#13Fixed Window Rate Limiter

#### Free test cases & hints

#14Token Bucket Rate Limiter

#### Free test cases & hints

#15Leaky Bucket Rate Limiter

#### Free test cases & hints

#16Least-recently used cache (MRU)

#17Game of Life

#### Free test cases & hints

#18Find triplets that sum to a target ('3Sum')

#### Free test cases & hints

#19Reverse Polish Notation calculator

#20Mars Rover

#### Free test cases & hints

#21Find indices of tuples that sum to a target (Two Sum)

#### Free test cases & hints

#22Sliding Window Rate Limiter

#### Free test cases & hints

#23Compute modulo of an exponent without exponentiation

#### Free test cases & hints

#24Count pairs of a given expected sum

#### Free test cases & hints

#25Establish execution order from dependencies

#### Free test cases & hints

#26Check a binary tree is balanced

#### Free test cases & hints

#28Reverse first n elements of a queue

#### Free test cases & hints

#29Least-recently used cache (LRU)

#### Free test cases & hints

#30Find height of binary tree

#### Free test cases & hints

#31Check a binary tree is a search tree

#### Free test cases & hints

#32Make a binary search tree (Red-Black tree)

#### Free test cases & hints

#33Check a directed graph has a routing between two nodes

#### Free test cases & hints

#34Longest common prefix of strings

#### Free test cases & hints

#35Check if a directed graph has cycles

#### Free test cases & hints

#37Count passing cars

#### Free test cases & hints

#38Remove duplicates from an unsorted List

#### Free test cases & hints

#39Make a queue using Maps

#### Free test cases & hints

#40Make a queue using stacks (Lists in Scala)

#### Free test cases & hints

#41Single-elimination tournament tree

#### Free test cases & hints

#42Compute the length of longest valid parentheses

#### Free test cases & hints

#43Binary search in a rotated sorted array

#### Free test cases & hints

#44Find combinations adding up to N (unique)

#### Free test cases & hints

#45Find the index of a substring ('indexOf')

#### Free test cases & hints

#46Reverse bits of an integer

#### Free test cases & hints

#47Find k closest elements to a value in a sorted Array

#### Free test cases & hints

#48Reshape a matrix

#### Free test cases & hints

#49Remove duplicates from a sorted list (Sliding)

#### Free test cases & hints

#50Remove duplicates from a sorted list (state machine)

#### Free test cases & hints

#51Find combinations adding up to N (non-unique)

#### Free test cases & hints

#52Compute single-digit sum of digits

#### Free test cases & hints

#54Tic Tac Toe MinMax solve

#### Free test cases & hints

#55Compute nth row of Pascal's triangle

#### Free test cases & hints

#56Print Alphabet Diamond

#### Free test cases & hints

#57Reverse a String's words efficiently

#### Free test cases & hints

#58Monitor success rate of a process that may fail

#### Free test cases & hints

#59QuickSelect Selection Algorithm

#### Free test cases & hints

#60Rotate a matrix by 90 degrees

#### Free test cases & hints

#61Read a matrix as a spiral

#### Free test cases & hints

#62Count number of contiguous countries by colors

#### Free test cases & hints

#63Length of the longest common substring

#### Free test cases & hints

#64Find minimum missing positive number in a sequence

#### Free test cases & hints

#65Binary search a generic Array

#### Free test cases & hints

#66Run-length encoding (RLE) Decoder

#### Free test cases & hints

#67Run-length encoding (RLE) Encoder

#### Free test cases & hints

#68Find the contiguous slice with the minimum average

#### Free test cases & hints

#69Tic Tac Toe board check

#### Free test cases & hints

#70Find the minimum absolute difference of two partitions

#### Free test cases & hints

#71Compute a Roman numeral for an Integer, and vice-versa

#### Free test cases & hints

#72Quick Sort sorting algorithm in pure immutable Scala

#### Free test cases & hints

#73Fibonacci in purely functional immutable Scala

#### Free test cases & hints

#74Count numbers divisible by another

#### Free test cases & hints

#75Is an array a permutation?

#### Free test cases & hints

#76Merge Sort: stack-safe, tail-recursive

#### Free test cases & hints

#77Closest pair of coordinates in a 2D plane

#### Free test cases & hints

#78Counting inversions of a sequence

#### Free test cases & hints

#79Rotate Array right in pure-functional Scala

#### Free test cases & hints

#80Count factors of a number

#### Free test cases & hints

#81Merge Sort: in pure immutable Scala

#### Free test cases & hints

#82Longest increasing sub-sequence length

#### Free test cases & hints

#83Matching parentheses algorithm with a state machine

#### Free test cases & hints

#85Count number of changes for making an anagram

#### Free test cases & hints

#86Check if a number is a palindrome

#### Free test cases & hints

#87Compute maximum sum of subarray (Kadane's algorithm)

#### Free test cases & hints

#88Check if a String is a palindrome

#### Free test cases & hints

#89Find sub-array with the maximum sum

#### Free test cases & hints

#90Traverse a tree Depth-First

#### Free test cases & hints

#91Maximum wait at a fuel station

#### Available 5th April

#92Count dist intersections

#### Available 20th April

#93Print a binary tree

#### Available 8th May

#94Find the longest palindrome within a string

#### Available 20th May

#95Median of two sorted arrays

#### Available 8th June

#96Check word in grid (depth-first search)

#### Available 20th June

#97Check word in grid (stack-safe)

#### Available 8th July

#98Merge intervals

#### Available 20th July

#99Check Sudoku board

#### Available 8th August

#100Print a binary tree vertically

#### Available 20th August

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