Code Challenges

Get better at coding with practice problems.

Coding Challenges

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Two Pointers Linked List

Intermediate

Implement the `sortLinkedListValues` method that sorts linked list values and returns the sorted list.

Two Pointers Linked List

Intermediate

Implement the `reorderLinkedListValues` method that reorders linked list values in first-last alternating order.

Two Pointers Linked List

Intermediate

Implement the `intersectionLinkedListValue` method that returns the first common value between two linked lists.

Two Pointers Linked List

Intermediate

Implement the `addTwoNumbersLinkedList` method that adds two numbers represented by linked lists and returns the result list.

Two Pointers Linked List

Learner

Implement the `palindromeLinkedListCheck` method that checks whether the linked list values form a palindrome.

Two Pointers Linked List

Learner

Implement the `middleNodeLinkedList` method that returns the value stored at the middle node of the linked list.

Two Pointers Linked List

Intermediate

Implement the `removeNthNodeFromEnd` method that removes the nth node from the end and returns the updated list values.

Two Pointers Linked List

Learner

Implement the `mergeTwoSortedLinkedLists` method that merges two sorted linked lists and returns the sorted values.

Two Pointers Linked List

Intermediate

Implement the `detectCycleLinkedListValues` method that checks whether the linked list has a cycle at the given position.

Two Pointers Linked List

Learner

Implement the `reverseLinkedListInterview` method that returns linked list values after reversing the list.

Array Sorting Two Pointers

Intermediate

Implement the `boatsToSavePeopleCount` method that returns the minimum boats needed under the weight limit.

Array Sorting Two Pointers

Learner

Implement the `sortedSquaresTwoPointers` method that returns squares of sorted values in sorted order.

Array Sorting Two Pointers

Learner

Implement the `mergeSortedArrayInPlaceResult` method that merges two sorted arrays into a sorted result.

Array Sorting Two Pointers

Intermediate

Implement the `fourSumPairCountSimple` method that counts quadruplets that produce the target sum.

Array Sorting Two Pointers

Learner

Implement the `minimumDifferencePairSorted` method that returns the smallest difference between any pair after sorting.

Array Sorting Two Pointers

Learner

Implement the `validPalindromeAfterOneRemoval` method that checks whether a text can become a palindrome after removing at most one character.

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.