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

Loop Array Hash Map Counting Prefix Sum

Intermediate

Implement the `maximumSubarraySum` method that returns the largest sum of any contiguous subarray.

Loop Array Hash Map Counting Prefix Sum

Learner

Implement the `findTwoSumIndices` method that returns indices of two numbers whose sum equals the target.

Array Dynamic Programming Greedy

Intermediate

Implement the `maximumProfitMultipleTransactions` method that returns the maximum stock profit using multiple valid transactions.

Array Dynamic Programming Greedy

Learner

Implement the `maximumProfitSingleTransaction` method that returns the best stock profit using at most one buy and one sell.

String Dynamic Programming Memoization Tabulation

Proficient

Implement the `wordBreakPossible` method that checks whether the text can be segmented using the given dictionary words.

String Dynamic Programming Tabulation

Intermediate

Implement the `decodeWaysCount` method that counts how many ways a digit string can be decoded.

Array Dynamic Programming Matrix Tabulation

Proficient

Implement the `maximumSquareOfOnes` method that returns the area of the largest square containing only 1 values.

Array Dynamic Programming Greedy

Learner

Implement the `canReachLastIndex` method that checks whether the last index can be reached from the first index.

Array Dynamic Programming Tabulation

Proficient

Implement the `minimumJumpsToReachEnd` method that finds the minimum jumps required to reach the last index.

Math Dynamic Programming Tabulation

Intermediate

Implement the `maximumProductCutting` method that finds the maximum product obtainable by cutting an integer into parts.

Array Dynamic Programming Tabulation

Proficient

Implement the `rodCuttingMaximumProfit` method that finds the maximum profit obtainable by cutting a rod into pieces.

String Dynamic Programming Tabulation

Proficient

Implement the `minimumInsertionsToPalindrome` method that finds the minimum insertions required to make the text a palindrome.

String Dynamic Programming Tabulation

Proficient

Implement the `longestPalindromicSubsequenceLength` method that returns the length of the longest palindromic subsequence.

Array Dynamic Programming Matrix Tabulation

Intermediate

Implement the `uniquePathsWithBlockedCells` method that counts grid paths while avoiding blocked cells.

Math Dynamic Programming Matrix Tabulation

Learner

Implement the `uniquePathsInGrid` method that counts paths from the top-left cell to the bottom-right cell in a grid.

Array Dynamic Programming Matrix Tabulation

Intermediate

Implement the `minimumPathSumGrid` method that finds the minimum path sum from the top-left to the bottom-right of a grid.

Array Dynamic Programming Matrix Tabulation

Intermediate

Implement the `maximumPathSumGrid` method that finds the maximum path sum from the top-left to the bottom-right of a grid.

Array Dynamic Programming Tabulation

Proficient

Implement the `countSubsetSumWays` method that counts how many subsets produce the target sum.

Array Dynamic Programming Tabulation

Intermediate

Implement the `subsetSumExists` method that checks whether any subset can produce the target sum.