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 `nextPermutationRankChange` method that returns the next lexicographical permutation of the array.

Loop Array Hash Map Counting Prefix Sum

Learner

Implement the `maximumConsecutiveOnes` method that returns the longest run of consecutive 1 values.

Loop Array Hash Map Counting Prefix Sum

Intermediate

Implement the `mergeOverlappingIntervalsCount` method that returns how many intervals remain after merging all overlaps.

Loop Array Hash Map Counting Prefix Sum

Learner

Implement the `missingNumberZeroToN` method that finds the missing number from the range 0 to n.

Loop Array Hash Map Counting Prefix Sum

Learner

Implement the `findDuplicateNumber` method that returns a duplicate value from the array.

Loop Array Hash Map Counting Prefix Sum

Intermediate

Implement the `rotateArrayRightK` method that returns the array after rotating it k positions to the right.

Loop Array Hash Map Counting Prefix Sum

Intermediate

Implement the `productArrayExceptSelf` method that returns an array where each value is the product of all other values.

Loop Array Hash Map Counting Prefix Sum

Learner

Implement the `majorityElementValue` method that returns the value that appears more than half of the time.

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 Prefix Sum Sliding Window

Intermediate

Implement the `maximumSubarraySumFixedLength` method that finds the maximum sum of any contiguous subarray of length k.

Array Prefix Sum Dynamic Programming

Intermediate

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