linked list pointer Pattern
59 problems
Pattern pages help build reusable solving frames. Identify signals first, then explain state, transition, and edge handling.
Recognition Signals
- Check how you handle carries at each node and whether your pointers correctly traverse both lists.
- Notice if you address unequal list lengths without skipping nodes or losing digits.
- Look for knowledge of linked-list pointer manipulation.
Solve Flow
- 1. Define the active state/window.
- 2. Update state while preserving invariants.
- 3. Validate with edge-heavy examples.
Common Misses
- Failing to propagate carry to a new node after both lists are processed.
- Not properly handling the edge case where the list has only one element or when n is equal to the list length.
- Failing to handle the case where one list is empty.
Recommended Ladder
Add Two Numbers
Add Two Numbers requires careful linked-list pointer manipulation to sum digits while handling carries efficiently in in…
Remove Nth Node From End of List
Remove the nth node from the end of a linked list using a two-pointer approach to solve efficiently.
Merge Two Sorted Lists
Merge two sorted linked lists by splicing nodes into one sorted list using linked-list pointer manipulation and recursio…
Merge k Sorted Lists
Merge k Sorted Lists requires efficiently combining multiple sorted linked lists into one using pointers and priority qu…
Swap Nodes in Pairs
Learn how to swap every adjacent linked-list pair by rewiring nodes safely without changing values or breaking the remai…
Reverse Nodes in k-Group
Reverse Nodes in k-Group challenges you to reverse segments of a linked list in groups of size k.
Rotate List
Rotate a singly linked list to the right by k positions using careful pointer manipulation and two-pointer traversal tec…
Remove Duplicates from Sorted List II
Remove duplicates from a sorted linked list, leaving only distinct values, and return the modified list in sorted order.
Remove Duplicates from Sorted List
Efficiently remove duplicates from a sorted linked list using precise pointer manipulation while maintaining node order …
Partition List
Partition a linked list such that all nodes less than x come before nodes greater than or equal to x while preserving re…
Reverse Linked List II
Reverse a segment of a singly linked list from position left to right using precise pointer manipulation techniques.
Convert Sorted List to Binary Search Tree
Convert a sorted singly linked list into a height-balanced BST using pointer manipulation and divide-and-conquer recursi…
Flatten Binary Tree to Linked List
Flatten a binary tree into a right-skewed linked list by manipulating pointers following a pre-order traversal, handling…
Populating Next Right Pointers in Each Node
Connect each node across every level by reusing established next links to traverse a perfect binary tree without extra q…
Populating Next Right Pointers in Each Node II
Populate each next pointer in a binary tree to its immediate right node, handling nulls and uneven levels efficiently us…
Copy List with Random Pointer
This problem requires copying a linked list where each node has a random pointer in addition to the next pointer.
Linked List Cycle
Determine if a given linked list contains a cycle using pointer manipulation or hashing, focusing on detecting repeated …
Linked List Cycle II
Identify the start of a cycle in a linked list using pointer manipulation, efficiently handling edge cases without modif…
Reorder List
Reorder List requires careful pointer manipulation in a singly linked list to interleave nodes from the ends without alt…
LRU Cache
Implement an efficient LRU Cache using hash table and doubly-linked list to achieve O(1) operations for get and put.
Insertion Sort List
Sort a singly linked list using insertion sort by carefully manipulating pointers to maintain a sorted order efficiently…
Sort List
Sort List requires sorting a singly linked list efficiently using pointer manipulation and merge sort for optimal perfor…
Intersection of Two Linked Lists
Given two linked lists, find the node where they intersect or return null if they do not.
Remove Linked List Elements
Remove all nodes from a linked list that have a specific value, adjusting pointers to preserve the rest of the list.
Palindrome Linked List
Solve Palindrome Linked List by finding the midpoint, reversing the second half, and comparing mirrored nodes in linear …
Delete Node in a Linked List
Delete Node in a Linked List focuses on pointer manipulation to delete a node in a singly linked list without access to …
Odd Even Linked List
Reorder a singly linked list by grouping odd-indexed nodes first, followed by even-indexed nodes while preserving relati…
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Linked List Random Node
Select a random node from a singly linked list ensuring uniform probability using efficient pointer techniques and reser…
Flatten a Multilevel Doubly Linked List
Flatten a multilevel doubly linked list by correctly updating next, prev, and child pointers to create a single-level se…
All O`one Data Structure
Implement a data structure that tracks string counts and retrieves max or min keys efficiently in constant time.
Add Two Numbers II
Add Two Numbers II involves summing two numbers represented as linked lists and returning the result as a new linked lis…
LFU Cache
Implement an LFU Cache using linked-list pointer manipulation with constant-time get and put operations for interview sc…
Design Circular Queue
Design a circular queue that allows efficient FIFO operations using linked-list pointer manipulation to optimize space u…
Design Circular Deque
Design and implement a circular deque using linked-list pointer manipulation, ensuring efficient insertion and deletion …
Design Linked List
Implement a custom linked list supporting head, tail, index insertions, retrieval, and deletions efficiently with pointe…
Split Linked List in Parts
Efficiently split a singly linked list into k consecutive parts, balancing sizes while preserving the original node orde…
Middle of the Linked List
Find the middle node of a singly linked list using a two-pointer technique.
Next Greater Node In Linked List
Find the next greater value for each node in a linked list using monotonic stack techniques for efficient traversal.
Remove Zero Sum Consecutive Nodes from Linked List
Remove zero-sum consecutive nodes from a linked list by iterating through it, repeatedly deleting sequences that sum to …
Design Skiplist
Implement a Skiplist efficiently using linked-list pointer manipulation to support search, add, and erase operations in …
Convert Binary Number in a Linked List to Integer
Convert a binary number represented in a linked list to its decimal value using efficient pointer manipulation.
Linked List in Binary Tree
Determine if a linked list is represented as a downward path in a binary tree using pointer traversal and recursive chec…
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Implement a browser history tracker with back, forward, and visit operations using linked-list pointer manipulation effi…
Merge In Between Linked Lists
Merge a second linked list into a first by removing a specified range of nodes, testing precise pointer updates and list…
Design Front Middle Back Queue
Implement a queue that efficiently handles push and pop operations at the front, middle, and back using pointer manipula…
Swapping Nodes in a Linked List
Swap nodes in a linked list using linked-list pointer manipulation and two pointers to solve this medium difficulty prob…
Design Authentication Manager
Implement an AuthenticationManager using linked-list pointer manipulation and a hash map to track token expirations effi…
Find the Minimum and Maximum Number of Nodes Between Critical Points
Find the minimum and maximum number of nodes between critical points in a linked list by identifying local minima and ma…
Reverse Nodes in Even Length Groups
Reverse nodes in even length groups while keeping the odd-length groups intact in a given linked list.
Delete the Middle Node of a Linked List
Efficiently remove the middle node from a linked list using two-pointer techniques and careful pointer updates to mainta…
Maximum Twin Sum of a Linked List
Find the maximum twin sum in a linked list by manipulating pointers efficiently and leveraging stack or reversal techniq…
Merge Nodes in Between Zeros
This problem requires merging nodes between zeros in a linked list by summing up the values between consecutive zeros.
Steps to Make Array Non-decreasing
Determine the minimum steps to make an array non-decreasing using linked-list pointer manipulation and monotonic stack t…
Design a Text Editor
Design a text editor that supports text manipulation and cursor navigation operations efficiently with linked-list-based…
Spiral Matrix IV
In this problem, you need to generate a matrix filled with values from a linked list in a spiral order.
Remove Nodes From Linked List
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Insert Greatest Common Divisors in Linked List
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Double a Number Represented as a Linked List
Double a number represented as a linked list by carefully managing node values and carries with pointer traversal techni…