Code Challenges

Get better at coding with practice problems.

Coding Challenges

Select a problem, write code, run test cases, and submit your solution.

Start with beginner challenges

Array Hash Map Counting

Intermediate

Implement the `isomorphicStringsCheck` method that checks whether two strings follow the same character mapping pattern.

Array Hash Map Counting

Learner

Implement the `containsDuplicateWithinK` method that checks whether duplicate values appear within distance k.

Array Hash Map Counting

Intermediate

Implement the `subarraySumEqualsKCount` method that counts subarrays whose sum equals k.

Array Hash Map Counting

Intermediate

Implement the `longestConsecutiveSequenceLength` method that returns the length of the longest consecutive number sequence.

Array Hash Map Counting

Learner

Implement the `twoSumUsingMap` method that returns two indices that form the target sum using a hash map.

Array String Dynamic Programming Memoization Tabulation

Guru

Implement the `regularExpressionMatchSimple` method that checks whether text matches a simplified regular expression pattern.

Array String Dynamic Programming Memoization Tabulation

Guru

Implement the `palindromePartitionMinCuts` method that returns the minimum cuts needed to split text into palindrome parts.

Array String Dynamic Programming Memoization Tabulation

Proficient

Implement the `maximumSquareAreaOnes` method that returns the area of the largest all-ones square in a matrix.

Array String Dynamic Programming Memoization Tabulation

Proficient

Implement the `wordBreakDpPossible` method that checks whether dynamic programming can segment the text into dictionary words.

Array String Dynamic Programming Memoization Tabulation

Guru

Implement the `editDistanceDpOperations` method that returns the minimum edit operations using dynamic programming.

Array String Dynamic Programming Memoization Tabulation

Proficient

Implement the `longestCommonSubsequenceDpLength` method that returns the LCS length using dynamic programming.

Array String Dynamic Programming Memoization Tabulation

Proficient

Implement the `longestIncreasingSubsequenceOptimizedLength` method that returns the LIS length using optimized binary-search based logic.

Array String Dynamic Programming Memoization Tabulation

Intermediate

Implement the `coinChangeCombinationCount` method that counts coin combinations that can make the amount.

Array String Dynamic Programming Memoization Tabulation

Proficient

Implement the `coinChangeMinimumCoins` method that returns the minimum number of coins needed to make the amount.

Array String Dynamic Programming Memoization Tabulation

Intermediate

Implement the `houseRobberMaximumAmount` method that returns the maximum amount that can be robbed without choosing adjacent houses.

Array Sorting Binary Search Two Pointers

Proficient

Implement the `aggressiveCowsDistance` method that maximizes the minimum distance between placed cows.

Array Sorting Binary Search Two Pointers

Proficient

Implement the `allocateMinimumPagesSimple` method that minimizes the maximum pages assigned to any student.

Array Sorting Binary Search Two Pointers

Intermediate

Implement the `findPeakUsingBinarySearch` method that returns a peak element index using binary search.

Array Sorting Binary Search Two Pointers

Intermediate

Implement the `sortColorsOnePass` method that sorts three color values in one pass.