EPI Judge Haskell

EPIJudgeHaskell provides EPIJudge problems in Haskell.

Project status

The project is under active development and I am working on translating the problems to Haskell along with their solutions. Please see the table at the bottom of this page to get the current status of problems.

Test Framework

The project comes with a Haskell Test Framework (see epi_judge_haskell_solutions/TestFramework) just like we have one for Python, Java, and C++. It uses the test data provided in EPIJudge without any modifications. The framework works for the problems that have already been translated to Haskell but might not work for pending ones. It will be updated as per the requirements of pending problems when they are translated. I am using attoparsec to parse test data. As of writing it is generally faster (without any effort at optimizing) than the ones in other languages.

Haskell dependencies

The project uses the following Haskell dependencies. All of them can be downloaded using cabal.

1. attoparsec
2. vector
3. random
4. deepseq

Running the judge from the command line

Haskell

Compile and run a specific program:

$ make <program_name> 

Example:

$ make parity

Example run

Makefile is provided to ease the running of problems. Simply run make <problem_name> within epi_judge_haskell or epi_judge_haskell_solutions directories to run the desired problem. The command will compile the problem file, run it against the test data, and print the results.

Successful run

$ make isValidSudoku
Compiling isValidSudoku.hs
ghc  -O2 -fno-omit-yields -outputdir build  -o build/isValidSudoku isValidSudoku.hs
Loaded package environment from /Users/home/.ghc/x86_64-darwin-8.8.1/environments/default
[4 of 4] Compiling Main             ( isValidSudoku.hs, build/Main.o )
Linking build/isValidSudoku ...
Running isValidSudoku
build/isValidSudoku
Test PASSED (   745/745) [        13 us]
Average running time:         12 us
Median running time:          13 us
*** You've passed ALL tests. Congratulations! ***

Failed run

$ make sortedArrayRemoveDups
Compiling sortedArrayRemoveDups.hs
ghc  -O2 -outputdir build  -o build/sortedArrayRemoveDups sortedArrayRemoveDups.hs
Loaded package environment from /Users/home/.ghc/x86_64-darwin-8.8.1/environments/default
[4 of 4] Compiling Main             ( sortedArrayRemoveDups.hs, build/Main.o )
Linking build/sortedArrayRemoveDups ...
Running sortedArrayRemoveDups
build/sortedArrayRemoveDups
Test FAILED (    1/2003)
Arguments
	Input1:           [-8,-7,-6,-5,-5,-4,-3,-1,-1,0,0,2,2,2,4]

Failure info
	explanation:      TODO
	expected:         [-8,-7,-6,-5,-4,-3,-1,0,2,4]
	result:           [-8,-7,-6,-5,-5,-4,-3,-1,-1,0,0,2,2,2,4]

FAQ

• How can I contact the authors?

  • Please feel free to send me questions and feedback - amoghdroid09@gmail.com

• What Haskell compiler is supported?

  • Any recent GHC version should work. I have developed the project using GHC 8.8.1.

Problem to Program Mapping

(You may have to scroll to the right to view the Python column.)

Problem	Haskell	C++	Java	Python
Bootcamp: Primitive Types	countBits.hs	count_bits.cc	CountBits.java	count_bits.py
Computing the parity of a word	parity.hs	parity.cc	Parity.java	parity.py
Swap bits	swapBits.hs	swap_bits.cc	SwapBits.java	swap_bits.py
Reverse bits	reverseBits.hs	reverse_bits.cc	ReverseBits.java	reverse_bits.py
Find a closest integer with the same weight	closestIntSameWeight.hs	closest_int_same_weight.cc	ClosestIntSameWeight.java	closest_int_same_weight.py
Compute x * y without arithmetical operators	primitiveMultiply.hs	primitive_multiply.cc	PrimitiveMultiply.java	primitive_multiply.py
Compute x/y	primitiveDivide.hs	primitive_divide.cc	PrimitiveDivide.java	primitive_divide.py
Compute x^y	powerXY.hs	power_x_y.cc	PowerXY.java	power_x_y.py
Reverse digits	reverseDigits.hs	reverse_digits.cc	ReverseDigits.java	reverse_digits.py
Check if a decimal integer is a palindrome	isNumberPalindromic.hs	is_number_palindromic.cc	IsNumberPalindromic.java	is_number_palindromic.py
Generate uniform random numbers	uniformRandomNumber.hs	uniform_random_number.cc	UniformRandomNumber.java	uniform_random_number.py
Rectangle intersection	rectangleIntersection.hs	rectangle_intersection.cc	RectangleIntersection.java	rectangle_intersection.py
Bootcamp: Arrays	evenOddArray.hs	even_odd_array.cc	EvenOddArray.java	even_odd_array.py
The Dutch national flag problem	dutchNationalFlag.hs	dutch_national_flag.cc	DutchNationalFlag.java	dutch_national_flag.py
Increment an arbitrary-precision integer	intAsArrayIncrement.hs	int_as_array_increment.cc	IntAsArrayIncrement.java	int_as_array_increment.py
Multiply two arbitrary-precision integers	intAsArrayMultiply.hs	int_as_array_multiply.cc	IntAsArrayMultiply.java	int_as_array_multiply.py
Advancing through an array	advanceByOffsets.hs	advance_by_offsets.cc	AdvanceByOffsets.java	advance_by_offsets.py
Delete duplicates from a sorted array	sortedArrayRemoveDups.hs	sorted_array_remove_dups.cc	SortedArrayRemoveDups.java	sorted_array_remove_dups.py
Buy and sell a stock once	buyAndSellStock.hs	buy_and_sell_stock.cc	BuyAndSellStock.java	buy_and_sell_stock.py
Buy and sell a stock twice	buyAndSellStockTwice.hs	buy_and_sell_stock_twice.cc	BuyAndSellStockTwice.java	buy_and_sell_stock_twice.py
Computing an alternation	alternatingArray.hs	alternating_array.cc	AlternatingArray.java	alternating_array.py
Enumerate all primes to n	primeSieve.hs	prime_sieve.cc	PrimeSieve.java	prime_sieve.py
Permute the elements of an array	applyPermutation.hs	apply_permutation.cc	ApplyPermutation.java	apply_permutation.py
Compute the next permutation	nextPermutation.hs	next_permutation.cc	NextPermutation.java	next_permutation.py
Sample offline data	offlineSampling.hs	offline_sampling.cc	OfflineSampling.java	offline_sampling.py
Sample online data	onlineSampling.hs	online_sampling.cc	OnlineSampling.java	online_sampling.py
Compute a random permutation	randomPermutation.hs	random_permutation.cc	RandomPermutation.java	random_permutation.py
Compute a random subset	randomSubset.hs	random_subset.cc	RandomSubset.java	random_subset.py
Generate nonuniform random numbers	nonUniformRandomNumber.hs	nonuniform_random_number.cc	NonuniformRandomNumber.java	nonuniform_random_number.py
The Sudoku checker problem	isValidSudoku.hs	is_valid_sudoku.cc	IsValidSudoku.java	is_valid_sudoku.py
Compute the spiral ordering of a 2D array	spiralOrderingSegments.hs	spiral_ordering_segments.cc	SpiralOrderingSegments.java	spiral_ordering_segments.py
Rotate a 2D array	matrixRotation.hs	matrix_rotation.cc	MatrixRotation.java	matrix_rotation.py
Compute rows in Pascal's Triangle	pascalTriangle.hs	pascal_triangle.cc	PascalTriangle.java	pascal_triangle.py
Interconvert strings and integers	stringIntegerInterconversion.hs	string_integer_interconversion.cc	StringIntegerInterconversion.java	string_integer_interconversion.py
Base conversion	convertBase.hs	convert_base.cc	ConvertBase.java	convert_base.py
Compute the spreadsheet column encoding	spreadsheetEncoding.hs	spreadsheet_encoding.cc	SpreadsheetEncoding.java	spreadsheet_encoding.py
Replace and remove	replaceAndRemove.hs	replace_and_remove.cc	ReplaceAndRemove.java	replace_and_remove.py
Test palindromicity	isStringPalindromicPunctuation.hs	is_string_palindromic_punctuation.cc	IsStringPalindromicPunctuation.java	is_string_palindromic_punctuation.py
Reverse all the words in a sentence	reverseWords.hs	reverse_words.cc	ReverseWords.java	reverse_words.py
Compute all mnemonics for a phone number	phoneNumberMnemonic.hs	phone_number_mnemonic.cc	PhoneNumberMnemonic.java	phone_number_mnemonic.py
The look-and-say problem	lookAndSay.hs	look_and_say.cc	LookAndSay.java	look_and_say.py
Convert from Roman to decimal	romanToInteger.hs	roman_to_integer.cc	RomanToInteger.java	roman_to_integer.py
Compute all valid IP addresses	validIpAddresses.hs	valid_ip_addresses.cc	ValidIpAddresses.java	valid_ip_addresses.py
Write a string sinusoidally	snakeString.hs	snake_string.cc	SnakeString.java	snake_string.py
Implement run-length encoding	runLengthCompression.hs	run_length_compression.cc	RunLengthCompression.java	run_length_compression.py
Find the first occurrence of a substring	substringMatch.hs	substring_match.cc	SubstringMatch.java	substring_match.py
Bootcamp: Linked Lists	searchInList.hs	search_in_list.cc	SearchInList.java	search_in_list.py
Bootcamp: Linked Lists	insertInList.hs	insert_in_list.cc	InsertInList.java	insert_in_list.py
Bootcamp: Linked Lists	deleteFromList.hs	delete_from_list.cc	DeleteFromList.java	delete_from_list.py
Merge two sorted lists	sortedListsMerge.hs	sorted_lists_merge.cc	SortedListsMerge.java	sorted_lists_merge.py
Reverse a single sublist	reverseSublist.hs	reverse_sublist.cc	ReverseSublist.java	reverse_sublist.py
Test for cyclicity	isListCyclic.hs	is_list_cyclic.cc	IsListCyclic.java	is_list_cyclic.py
Test for overlapping lists - lists are cycle-free	doTerminatedListsOverlap.hs	do_terminated_lists_overlap.cc	DoTerminatedListsOverlap.java	do_terminated_lists_overlap.py
Test for overlapping lists - lists may have cycles	doListsOverlap.hs	do_lists_overlap.cc	DoListsOverlap.java	do_lists_overlap.py
Delete a node from a singly linked list	deleteNodeFromList.hs	delete_node_from_list.cc	DeleteNodeFromList.java	delete_node_from_list.py
Remove the kth last element from a list	deleteKthLastFromList.hs	delete_kth_last_from_list.cc	DeleteKthLastFromList.java	delete_kth_last_from_list.py
Remove duplicates from a sorted list	removeDuplicatesFromSortedList.hs	remove_duplicates_from_sorted_list.cc	RemoveDuplicatesFromSortedList.java	remove_duplicates_from_sorted_list.py
Implement cyclic right shift for singly linked lists	listCyclicRightShift.hs	list_cyclic_right_shift.cc	ListCyclicRightShift.java	list_cyclic_right_shift.py
Implement even-odd merge	evenOddListMerge.hs	even_odd_list_merge.cc	EvenOddListMerge.java	even_odd_list_merge.py
Test whether a singly linked list is palindromic	isListPalindromic.hs	is_list_palindromic.cc	IsListPalindromic.java	is_list_palindromic.py
Implement list pivoting	pivotList.hs	pivot_list.cc	PivotList.java	pivot_list.py
Add list-based integers	intAsListAdd.hs	int_as_list_add.cc	IntAsListAdd.java	int_as_list_add.py
Implement a stack with max API	stackWithMax.hs	stack_with_max.cc	StackWithMax.java	stack_with_max.py
Evaluate RPN expressions	evaluateRpn.hs	evaluate_rpn.cc	EvaluateRpn.java	evaluate_rpn.py
Test a string over ''{,},(,),[,]'' for well-formedness	isValidParenthesization.hs	is_valid_parenthesization.cc	IsValidParenthesization.java	is_valid_parenthesization.py
Normalize pathnames	directoryPathNormalization.hs	directory_path_normalization.cc	DirectoryPathNormalization.java	directory_path_normalization.py
Compute buildings with a sunset view	sunsetView.hs	sunset_view.cc	SunsetView.java	sunset_view.py
Compute binary tree nodes in order of increasing depth	treeLevelOrder.hs	tree_level_order.cc	TreeLevelOrder.java	tree_level_order.py
Implement a circular queue	circularQueue.hs	circular_queue.cc	CircularQueue.java	circular_queue.py
Implement a queue using stacks	queueFromStacks.hs	queue_from_stacks.cc	QueueFromStacks.java	queue_from_stacks.py
Implement a queue with max API	queueWithMax.hs	queue_with_max.cc	QueueWithMax.java	queue_with_max.py
Test if a binary tree is height-balanced	isTreeBalanced.hs	is_tree_balanced.cc	IsTreeBalanced.java	is_tree_balanced.py
Test if a binary tree is symmetric	isTreeSymmetric.hs	is_tree_symmetric.cc	IsTreeSymmetric.java	is_tree_symmetric.py
Compute the lowest common ancestor in a binary tree	lowestCommonAncestor.hs	lowest_common_ancestor.cc	LowestCommonAncestor.java	lowest_common_ancestor.py
Compute the LCA when nodes have parent pointers	lowestCommonAncestorWithParent.hs	lowest_common_ancestor_with_parent.cc	LowestCommonAncestorWithParent.java	lowest_common_ancestor_with_parent.py
Sum the root-to-leaf paths in a binary tree	sumRootToLeaf.hs	sum_root_to_leaf.cc	SumRootToLeaf.java	sum_root_to_leaf.py
Find a root to leaf path with specified sum	pathSum.hs	path_sum.cc	PathSum.java	path_sum.py
Implement an inorder traversal without recursion	treeInorder.hs	tree_inorder.cc	TreeInorder.java	tree_inorder.py
Implement a preorder traversal without recursion	treePreorder.hs	tree_preorder.cc	TreePreorder.java	tree_preorder.py
Compute the kth node in an inorder traversal	kthNodeInTree.hs	kth_node_in_tree.cc	KthNodeInTree.java	kth_node_in_tree.py
Compute the successor	successorInTree.hs	successor_in_tree.cc	SuccessorInTree.java	successor_in_tree.py
Implement an inorder traversal with O(1) space	treeWithParentInorder.hs	tree_with_parent_inorder.cc	TreeWithParentInorder.java	tree_with_parent_inorder.py
Reconstruct a binary tree from traversal data	treeFromPreorderInorder.hs	tree_from_preorder_inorder.cc	TreeFromPreorderInorder.java	tree_from_preorder_inorder.py
Reconstruct a binary tree from a preorder traversal with markers	treeFromPreorderWithNull.hs	tree_from_preorder_with_null.cc	TreeFromPreorderWithNull.java	tree_from_preorder_with_null.py
Form a linked list from the leaves of a binary tree	treeConnectLeaves.hs	tree_connect_leaves.cc	TreeConnectLeaves.java	tree_connect_leaves.py
Compute the exterior of a binary tree	treeExterior.hs	tree_exterior.cc	TreeExterior.java	tree_exterior.py
Compute the right sibling tree	treeRightSibling.hs	tree_right_sibling.cc	TreeRightSibling.java	tree_right_sibling.py
Merge sorted files	sortedArraysMerge.hs	sorted_arrays_merge.cc	SortedArraysMerge.java	sorted_arrays_merge.py
Sort an increasing-decreasing array	sortIncreasingDecreasingArray.hs	sort_increasing_decreasing_array.cc	SortIncreasingDecreasingArray.java	sort_increasing_decreasing_array.py
Sort an almost-sorted array	sortAlmostSortedArray.hs	sort_almost_sorted_array.cc	SortAlmostSortedArray.java	sort_almost_sorted_array.py
Compute the k closest stars	kClosestStars.hs	k_closest_stars.cc	KClosestStars.java	k_closest_stars.py
Compute the median of online data	onlineMedian.hs	online_median.cc	OnlineMedian.java	online_median.py
Compute the k largest elements in a max-heap	kSmallestInHeap.hs	k_largest_in_heap.cc	KLargestInHeap.java	k_largest_in_heap.py
Search a sorted array for first occurrence of k	searchFirstKey.hs	search_first_key.cc	SearchFirstKey.java	search_first_key.py
Search a sorted array for entry equal to its index	searchEntryEqualToIndex.hs	search_entry_equal_to_index.cc	SearchEntryEqualToIndex.java	search_entry_equal_to_index.py
Search a cyclically sorted array	searchShiftedSortedArray.hs	search_shifted_sorted_array.cc	SearchShiftedSortedArray.java	search_shifted_sorted_array.py
Compute the integer square root	intSquareRoot.hs	int_square_root.cc	IntSquareRoot.java	int_square_root.py
Compute the real square root	realSquareRoot.hs	real_square_root.cc	RealSquareRoot.java	real_square_root.py
Search in a 2D sorted array	searchRowColSortedMatrix.hs	search_row_col_sorted_matrix.cc	SearchRowColSortedMatrix.java	search_row_col_sorted_matrix.py
Find the min and max simultaneously	searchForMinMaxInArray.hs	search_for_min_max_in_array.cc	SearchForMinMaxInArray.java	search_for_min_max_in_array.py
Find the kth largest element	kthLargestInArray.hs	kth_largest_in_array.cc	KthLargestInArray.java	kth_largest_in_array.py
Find the missing IP address	absentValueArray.hs	absent_value_array.cc	AbsentValueArray.java	absent_value_array.py
Find the duplicate and missing elements	searchForMissingElement.hs	search_for_missing_element.cc	SearchForMissingElement.java	search_for_missing_element.py
Bootcamp: Hash Tables	anagrams.hs	anagrams.cc	Anagrams.java	anagrams.py
Test for palindromic permutations	isStringPermutableToPalindrome.hs	is_string_permutable_to_palindrome.cc	IsStringPermutableToPalindrome.java	is_string_permutable_to_palindrome.py
Is an anonymous letter constructible?	isAnonymousLetterConstructible.hs	is_anonymous_letter_constructible.cc	IsAnonymousLetterConstructible.java	is_anonymous_letter_constructible.py
Implement an ISBN cache		lru_cache.cc	LruCache.java	lru_cache.py
Compute the LCA, optimizing for close ancestors		lowest_common_ancestor_close_ancestor.cc	LowestCommonAncestorCloseAncestor.java	lowest_common_ancestor_close_ancestor.py
Find the nearest repeated entries in an array		nearest_repeated_entries.cc	NearestRepeatedEntries.java	nearest_repeated_entries.py
Find the smallest subarray covering all values		smallest_subarray_covering_set.cc	SmallestSubarrayCoveringSet.java	smallest_subarray_covering_set.py
Find smallest subarray sequentially covering all values		smallest_subarray_covering_all_values.cc	SmallestSubarrayCoveringAllValues.java	smallest_subarray_covering_all_values.py
Find the longest subarray with distinct entries		longest_subarray_with_distinct_values.cc	LongestSubarrayWithDistinctValues.java	longest_subarray_with_distinct_values.py
Find the length of a longest contained interval		longest_contained_interval.cc	LongestContainedInterval.java	longest_contained_interval.py
Compute all string decompositions		string_decompositions_into_dictionary_words.cc	StringDecompositionsIntoDictionaryWords.java	string_decompositions_into_dictionary_words.py
Test the Collatz conjecture		collatz_checker.cc	CollatzChecker.java	collatz_checker.py
Compute the intersection of two sorted arrays		intersect_sorted_arrays.cc	IntersectSortedArrays.java	intersect_sorted_arrays.py
Merge two sorted arrays		two_sorted_arrays_merge.cc	TwoSortedArraysMerge.java	two_sorted_arrays_merge.py
Computing the h-index		h_index.cc	HIndex.java	h_index.py
Remove first-name duplicates		remove_duplicates.cc	RemoveDuplicates.java	remove_duplicates.py
Smallest nonconstructible value		smallest_nonconstructible_value.cc	SmallestNonconstructibleValue.java	smallest_nonconstructible_value.py
Render a calendar		calendar_rendering.cc	CalendarRendering.java	calendar_rendering.py
Merging intervals		interval_add.cc	IntervalAdd.java	interval_add.py
Compute the union of intervals		intervals_union.cc	IntervalsUnion.java	intervals_union.py
Partitioning and sorting an array with many repeated entries		group_equal_entries.cc	GroupEqualEntries.java	group_equal_entries.py
Team photo day - 1		is_array_dominated.cc	IsArrayDominated.java	is_array_dominated.py
Implement a fast sorting algorithm for lists		sort_list.cc	SortList.java	sort_list.py
Compute a salary threshold		find_salary_threshold.cc	FindSalaryThreshold.java	find_salary_threshold.py
Test if a binary tree satisfies the BST property		is_tree_a_bst.cc	IsTreeABst.java	is_tree_a_bst.py
Find the first key greater than a given value in a BST		search_first_greater_value_in_bst.cc	SearchFirstGreaterValueInBst.java	search_first_greater_value_in_bst.py
Find the k largest elements in a BST		k_largest_values_in_bst.cc	KLargestValuesInBst.java	k_largest_values_in_bst.py
Compute the LCA in a BST		lowest_common_ancestor_in_bst.cc	LowestCommonAncestorInBst.java	lowest_common_ancestor_in_bst.py
Reconstruct a BST from traversal data		bst_from_preorder.cc	BstFromPreorder.java	bst_from_preorder.py
Find the closest entries in three sorted arrays		minimum_distance_3_sorted_arrays.cc	MinimumDistance3SortedArrays.java	minimum_distance_3_sorted_arrays.py
Enumerate numbers of the form a + b sqrt(2)		a_b_sqrt2.cc	ABSqrt2.java	a_b_sqrt2.py
Build a minimum height BST from a sorted array		bst_from_sorted_array.cc	BstFromSortedArray.java	bst_from_sorted_array.py
Test if three BST nodes are totally ordered		descendant_and_ancestor_in_bst.cc	DescendantAndAncestorInBst.java	descendant_and_ancestor_in_bst.py
The range lookup problem		range_lookup_in_bst.cc	RangeLookupInBst.java	range_lookup_in_bst.py
Add credits		adding_credits.cc		AddingCredits.java
The Towers of Hanoi problem		hanoi.cc	Hanoi.java	hanoi.py
Generate all nonattacking placements of n-Queens		n_queens.cc	NQueens.java	n_queens.py
Generate permutations		permutations.cc	Permutations.java	permutations.py
Generate the power set		power_set.cc	PowerSet.java	power_set.py
Generate all subsets of size k		combinations.cc	Combinations.java	combinations.py
Generate strings of matched parens		enumerate_balanced_parentheses.cc	EnumerateBalancedParentheses.java	enumerate_balanced_parentheses.py
Generate palindromic decompositions		enumerate_palindromic_decompositions.cc	EnumeratePalindromicDecompositions.java	enumerate_palindromic_decompositions.py
Generate binary trees		enumerate_trees.cc	EnumerateTrees.java	enumerate_trees.py
Implement a Sudoku solver		sudoku_solve.cc	SudokuSolve.java	sudoku_solve.py
Compute a Gray code		gray_code.cc	GrayCode.java	gray_code.py
Bootcamp: Dynamic Programming		fibonacci.cc	Fibonacci.java	fibonacci.py
Bootcamp: Dynamic Programming		max_sum_subarray.cc	MaxSumSubarray.java	max_sum_subarray.py
Count the number of score combinations		number_of_score_combinations.cc	NumberOfScoreCombinations.java	number_of_score_combinations.py
Compute the Levenshtein distance		levenshtein_distance.cc	LevenshteinDistance.java	levenshtein_distance.py
Count the number of ways to traverse a 2D array		number_of_traversals_matrix.cc	NumberOfTraversalsMatrix.java	number_of_traversals_matrix.py
Compute the binomial coefficients		binomial_coefficients.cc	BinomialCoefficients.java	binomial_coefficients.py
Search for a sequence in a 2D array		is_string_in_matrix.cc	IsStringInMatrix.java	is_string_in_matrix.py
The knapsack problem		knapsack.cc	Knapsack.java	knapsack.py
The bedbathandbeyond.com problem		is_string_decomposable_into_words.cc	IsStringDecomposableIntoWords.java	is_string_decomposable_into_words.py
Find the minimum weight path in a triangle		minimum_weight_path_in_a_triangle.cc	MinimumWeightPathInATriangle.java	minimum_weight_path_in_a_triangle.py
Pick up coins for maximum gain		picking_up_coins.cc	PickingUpCoins.java	picking_up_coins.py
Count the number of moves to climb stairs		number_of_traversals_staircase.cc	NumberOfTraversalsStaircase.java	number_of_traversals_staircase.py
The pretty printing problem		pretty_printing.cc	PrettyPrinting.java	pretty_printing.py
Find the longest nondecreasing subsequence		longest_nondecreasing_subsequence.cc	LongestNondecreasingSubsequence.java	longest_nondecreasing_subsequence.py
Compute an optimum assignment of tasks		task_pairing.cc	TaskPairing.java	task_pairing.py
Schedule to minimize waiting time		minimum_waiting_time.cc	MinimumWaitingTime.java	minimum_waiting_time.py
The interval covering problem		minimum_points_covering_intervals.cc	MinimumPointsCoveringIntervals.java	minimum_points_covering_intervals.py
The interval covering problem		two_sum.cc	TwoSum.java	two_sum.py
The 3-sum problem		three_sum.cc	ThreeSum.java	three_sum.py
Find the majority element		majority_element.cc	MajorityElement.java	majority_element.py
The gasup problem		refueling_schedule.cc	RefuelingSchedule.java	refueling_schedule.py
Compute the maximum water trapped by a pair of vertical lines		max_trapped_water.cc	MaxTrappedWater.java	max_trapped_water.py
Compute the largest rectangle under the skyline		largest_rectangle_under_skyline.cc	LargestRectangleUnderSkyline.java	largest_rectangle_under_skyline.py
Search a maze		search_maze.cc	SearchMaze.java	search_maze.py
Paint a Boolean matrix		matrix_connected_regions.cc	MatrixConnectedRegions.java	matrix_connected_regions.py
Compute enclosed regions		matrix_enclosed_regions.cc	MatrixEnclosedRegions.java	matrix_enclosed_regions.py
Deadlock detection		deadlock_detection.cc	DeadlockDetection.java	deadlock_detection.py
Clone a graph		graph_clone.cc	GraphClone.java	graph_clone.py
Making wired connections		is_circuit_wirable.cc	IsCircuitWirable.java	is_circuit_wirable.py
Transform one string to another		string_transformability.cc	StringTransformability.java	string_transformability.py
Team photo day - 2		max_teams_in_photograph.cc	MaxTeamsInPhotograph.java	max_teams_in_photograph.py
Compute the greatest common divisor		gcd.cc	Gcd.java	gcd.py
Find the first missing positive entry		first_missing_positive_entry.cc	FirstMissingPositiveEntry.java	first_missing_positive_entry.py
Buy and sell a stock k times		buy_and_sell_stock_k_times.cc	BuyAndSellStockKTimes.java	buy_and_sell_stock_k_times.py
Compute the maximum product of all entries but one		max_product_all_but_one.cc	MaxProductAllButOne.java	max_product_all_but_one.py
Compute the longest contiguous increasing subarray		longest_increasing_subarray.cc	LongestIncreasingSubarray.java	longest_increasing_subarray.py
Rotate an array		rotate_array.cc	RotateArray.java	rotate_array.py
Identify positions attacked by rooks		rook_attack.cc	RookAttack.java	rook_attack.py
Justify text		left_right_justify_text.cc	LeftRightJustifyText.java	left_right_justify_text.py
Implement list zipping		zip_list.cc	ZipList.java	zip_list.py
Copy a postings list		copy_posting_list.cc	CopyPostingList.java	copy_posting_list.py
Compute the longest substring with matching parens		longest_substring_with_matching_parentheses.cc	LongestSubstringWithMatchingParentheses.java	longest_substring_with_matching_parentheses.py
Compute the maximum of a sliding window		max_of_sliding_window.cc	MaxOfSlidingWindow.java	max_of_sliding_window.py
Implement a postorder traversal without recursion		tree_postorder.cc	TreePostorder.java	tree_postorder.py
Compute fair bonuses		bonus.cc	Bonus.java	bonus.py
Search a sorted array of unknown length		search_unknown_length_array.cc	SearchUnknownLengthArray.java	search_unknown_length_array.py
Search in two sorted arrays		kth_largest_element_in_two_sorted_arrays.cc	KthLargestElementInTwoSortedArrays.java	kth_largest_element_in_two_sorted_arrays.py
Find the kth largest element - large n, small k		kth_largest_element_in_long_array.cc	KthLargestElementInLongArray.java	kth_largest_element_in_long_array.py
Find an element that appears only once		element_appearing_once.cc	ElementAppearingOnce.java	element_appearing_once.py
Find the line through the most points		line_through_most_points.cc	LineThroughMostPoints.java	line_through_most_points.py
Convert a sorted doubly linked list into a BST		sorted_list_to_bst.cc	SortedListToBst.java	sorted_list_to_bst.py
Convert a BST to a sorted doubly linked list		bst_to_sorted_list.cc	BstToSortedList.java	bst_to_sorted_list.py
Merge two BSTs		bst_merge.cc	BstMerge.java	bst_merge.py
Implement regular expression matching		regular_expression.cc	RegularExpression.java	regular_expression.py
Synthesize an expression		insert_operators_in_string.cc	InsertOperatorsInString.java	insert_operators_in_string.py
Count inversions		count_inversions.cc	CountInversions.java	count_inversions.py
Draw the skyline		drawing_skyline.cc	DrawingSkyline.java	drawing_skyline.py
Measure with defective jugs		defective_jugs.cc	DefectiveJugs.java	defective_jugs.py
Compute the maximum subarray sum in a circular array		maximum_subarray_in_circular_array.cc	MaximumSubarrayInCircularArray.java	maximum_subarray_in_circular_array.py
Determine the critical height		max_safe_height.cc	MaxSafeHeight.java	max_safe_height.py
Find the maximum 2D subarray		max_submatrix.cc	MaxSubmatrix.java	max_submatrix.py
Find the maximum 2D subarray		max_square_submatrix.cc	MaxSquareSubmatrix.java	max_square_submatrix.py
Implement Huffman coding		huffman_coding.cc	HuffmanCoding.java	huffman_coding.py
Trapping water		max_water_trappable.cc	MaxWaterTrappable.java	max_water_trappable.py
The heavy hitter problem		search_frequent_items.cc	SearchFrequentItems.java	search_frequent_items.py
Find the longest subarray whose sum <= k		longest_subarray_with_sum_constraint.cc	LongestSubarrayWithSumConstraint.java	longest_subarray_with_sum_constraint.py
Road network		road_network.cc	RoadNetwork.java	road_network.py
Test if arbitrage is possible		arbitrage.cc	Arbitrage.java	arbitrage.py