99 Elm Problems/Problems by Category

Lists

• Problem 1: Find the last element of a list
• Problem 2: Find the next to last element of a list
• Problem 3: Find the n-th element of a list
• Problem 4: Find the number of elements of a list
• Problem 5: Reverse a list
• Problem 6: Determine if a list is a palindrome
• Problem 7: Flatten a nested list structure
• Problem 8: Eliminate consecutive duplicates of list elements
• Problem 9: Pack consecutive duplicates of list elements into sublists
• Problem 10: Run length encode a list of tuples

Lists, continued

• Problem 11: Run-length encoding
• Problem 12: Run-length decoding
• Problem 14: Duplicate the elements
• Problem 15: Repeat each element
• Problem 16: Drop every N'th element
• Problem 17: Split a list into two parts
• Problem 18: Extract a sublist
• Problem 19: Rotate a list N places
• Problem 20: Remove the nth element

Lists again

• Problem 21: Insert an element
• Problem 22: Create a range of integers
• Problem 23: Randomly selected elements
• Problem 24: Randomly select from a set
• Problem 25: Generate a random permutation
• Problem 26: Generate combinations of a set
• Problem 27: Group elements into disjoint subsets
• Problem 28: Sort a list of lists

Arithmetic

• Problem 31: Check for prime
• Problem 32: Find greatest common divisor
• Problem 33: Check for coprime
• Problem 34: Calculate Euler's totient function
• Problem 35: Find prime factors
• Problem 36: List the prime factors
• Problem 37: Calculate Euler's totient function using prime factors
• Problem 39: List prime numbers within a range
• Problem 40: Goldbach's conjecture
• Problem 41: Search a range of numbers

Logic and Codes

• Problem 46: Define functions for logical operations
• Problem 47: Build truth tables for logical expressions
• Problem 48: Build truth tables for any logical expressions
• Problem 49: Gray codes
• Problem 50: Huffman codes

Binary Trees

• Problem 55: Construct a balanced binary tree
• Problem 56: Construct a symmetric binary tree
• Problem 57: Construct a binary search tree
• Problem 58: Generate and test paradigm
• Problem 59: Construct a height balanced binary tree
• Problem 60: Construct a height-balanced binary tree of N nodes

Binary Trees, continued

• Problem 61: Count the leaves
• Problem 62: Collect the internal nodes
• Problem 63: Construct a complete binary tree
• Problem 64: Plot node coordinates 1
• Problem 65: Plot node coordinates 2
• Problem 66: Plot node coordinates 3
• Problem 67: Represent a tree as a string
• Problem 68: Generate an ordered sequence
• Problem 69: Represent a tree with Dot Notation

Multi-way Trees

• Problem 70: Count the nodes of a multiway tree
• Problem 71: Internal path of a multiway tree
• Problem 72: Bottom-up sequence of a multiway tree
• Problem 73: Lisp representation of a multiway tree

Graphs

• Problem 80: Convert graphs representations
• Problem 81: Find all cyclic paths
• Problem 82: Find closed paths
• Problem 83: Find spanning trees
• Problem 84: Find the minimal spanning tree
• Problem 85: Determine if two graphs are isomorphic
• Problem 86: Calculate degree of a node
• Problem 87: Depth-first order graph traversal
• Problem 88: Connected components
• Problem 89: Check for bipartite graph

Puzzles

• Problem 90: Eight Queens
• Problem 91: The Knight's Tour
• Problem 92: Graceful Labeling
• Problem 93: Inserting operators
• Problem 94: Generate regular graphs
• Problem 95: Numbers to text
• Problem 96: Syntax checker
• Problem 97: Sudoku solver
• Problem 98: Nonogram solver
• Problem 99: Elm Problems: Crossword puzzle solver