Code Challenges

Get better at coding with practice problems.

Coding Challenges

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

Array Sorting Two Pointers

Proficient

Implement the `trappingRainWaterAmount` method that calculates how much rain water can be trapped between bars.

Array Sorting Two Pointers

Learner

Implement the `removeDuplicatesSortedArrayLength` method that returns the length after removing duplicates from a sorted array.

Array Sorting Two Pointers

Proficient

Implement the `threeSumTripletCount` method that counts unique triplets whose sum is zero.

Array Sorting Two Pointers

Intermediate

Implement the `containerWithMostWaterArea` method that returns the maximum water area formed by two vertical lines.

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.

Array Sorting Binary Search Two Pointers

Proficient

Implement the `medianTwoSortedArraysFloor` method that returns the floor of the median of two sorted arrays.

Array Sorting Binary Search Two Pointers

Intermediate

Implement the `findMinimumRotatedSorted` method that returns the minimum value from a rotated sorted array.

Array Sorting Binary Search Two Pointers

Proficient

Implement the `mergeSortInversionCount` method that counts inversions using merge-sort style processing.

Array Sorting Binary Search Two Pointers

Intermediate

Implement the `kthLargestQuickSelect` method that returns the kth largest value using selection logic.

Array Sorting Binary Search Two Pointers

Intermediate

Implement the `firstAndLastPositionBinary` method that returns the first and last target positions using binary search.

Array Sorting Binary Search Two Pointers

Intermediate

Implement the `searchRotatedSortedArrayImportant` method that searches for a target in a rotated sorted array using binary search.

Array Counting Sorting Two Pointers

Intermediate

Implement the `sortColorsThreeValues` method that sorts an array containing only three possible values.

Array Sorting Two Pointers

Guru

Implement the `findMedianOfTwoSortedArraysSimple` method that returns the floor of the median after combining two sorted arrays.

Array Sorting Merge Sort

Proficient

Implement the `countInversionsInArray` method that counts pairs that are out of sorted order in the array.

Array Hash Map Sorting

Intermediate

Implement the `minimumSwapsToSortSmallArray` method that returns the minimum number of swaps needed to sort the array.

Array Sorting Two Pointers

Learner

Implement the `mergeSortedWithoutDuplicates` method that merges two sorted arrays while removing duplicate values.