Reversing, reordering, and partitioning pointer chains with O(1) space
Rearrange nodes and pointers in-place by maintaining dummy heads, tracking previous/current/next pointers, and preserving detached segments.
Core Invariant: Pointer Surgery: Always save `temp = curr.next` before overwriting `curr.next`. Use a `dummy` node (`dummy.next = head`) to eliminate edge-case conditionals when mutating the head.
Random indexed access is required or node count is static and O(N) space is acceptable (convert to list).
def reverse_linked_list(head: ListNode | None) -> ListNode | None:
prev = None
curr = head
while curr:
next_temp = curr.next # 1. Save next reference before breaking link
curr.next = prev # 2. Reverse direction of pointer
prev = curr # 3. Advance prev forward
curr = next_temp # 4. Advance curr forward
return prev # New head of reversed list# | Problem | Difficulty | Top Companies↓ | Frequency | Acceptance | |
|---|---|---|---|---|---|---|
| #146 | LRU Cache Hash TableLinked ListDesignDoubly-Linked List | Medium | 100% | 47.6% | ||
| #23 | Merge k Sorted Lists Linked ListDivide and ConquerHeap (Priority Queue)Merge SortTournament Sort | Hard | 100% | 60.0% | ||
| #2 | Add Two Numbers Linked ListMathRecursion | Medium | 100% | 48.8% | ||
| #21 | Merge Two Sorted Lists Linked ListRecursion | Easy | 100% | 68.5% | ||
| #206 | Reverse Linked List Linked ListRecursion | Easy | 100% | 80.8% | ||
| #460 | LFU Cache Hash TableLinked ListDesignDoubly-Linked List | Hard | 100% | 49.7% | ||
| #25 | Reverse Nodes in k-Group Linked ListRecursion | Hard | 100% | 66.6% | ||
| #141 | Linked List Cycle Hash TableLinked ListTwo PointersFloyd's Cycle Finding Algorithm | Easy | 100% | 54.7% | ||
| #138 | Medium | 100% | 63.3% | |||
| #19 | Remove Nth Node From End of List Linked ListTwo Pointers | Medium | 100% | 52.0% | ||
| #622 | Design Circular Queue ArrayLinked ListDesignQueue | Medium | 100% | 55.0% | ||
| #143 | Reorder List Linked ListTwo PointersStackRecursion | Medium | 89% | 65.7% | ||
| #234 | Palindrome Linked List Linked ListTwo PointersStackRecursion | Easy | 93% | 0.6% | ||
| #355 | Design Twitter Hash TableLinked ListDesignHeap (Priority Queue) | Medium | 100% | 45.1% | ||
| #92 | Reverse Linked List II Linked List | Medium | 89% | 51.9% | ||
| #24 | Swap Nodes in Pairs Linked ListRecursion | Medium | 69% | 69.8% | ||
| #1797 | Design Authentication Manager Hash TableLinked ListDesignDoubly-Linked List | Medium | 100% | 58.7% | ||
| #142 | Linked List Cycle II Hash TableLinked ListTwo PointersFloyd's Cycle Finding Algorithm | Medium | 79% | 58.5% | ||
| #432 | All O`one Data Structure Hash TableLinked ListDesignDoubly-Linked List | Hard | 100% | 44.4% | ||
| #706 | Design HashMap ArrayHash TableLinked ListDesignHash Function | Easy | 100% | 66.7% | ||
| #1472 | Design Browser History ArrayLinked ListStackDesignDoubly-Linked ListData Stream | Medium | 100% | 78.4% | ||
| #876 | Middle of the Linked List Linked ListTwo Pointers | Easy | 88% | 82.1% | ||
| #160 | Intersection of Two Linked Lists Hash TableLinked ListTwo Pointers | Easy | 75% | 64.2% | ||
| #2296 | Design a Text Editor Linked ListStringStackDesignSimulationDoubly-Linked List | Hard | 100% | 0.5% | ||
| #328 | Odd Even Linked List Linked List | Medium | 67% | 62.6% | ||
| #1669 | Merge In Between Linked Lists Linked List | Medium | 100% | 83.1% | ||
| #716 | Max Stack Linked ListStackDesignDoubly-Linked ListOrdered Set | Hard | 100% | 46.0% | ||
| #82 | Remove Duplicates from Sorted List II Linked ListTwo Pointers | Medium | 100% | 52.1% | ||
| #237 | Delete Node in a Linked List Linked List | Medium | 88% | 84.1% | ||
| #61 | Rotate List Linked ListTwo Pointers | Medium | 100% | 42.9% | ||
| #109 | Convert Sorted List to Binary Search Tree Linked ListDivide and ConquerTreeBinary Search TreeBinary Tree | Medium | 100% | 0.7% | ||
| #1290 | Convert Binary Number in a Linked List to Integer Linked ListMath | Easy | 100% | 82.4% | ||
| #1206 | Design Skiplist Linked ListDesign | Hard | 100% | 59.8% | ||
| #203 | Remove Linked List Elements Linked ListRecursion | Easy | 75% | 54.9% | ||
| #116 | Populating Next Right Pointers in Each Node Linked ListTreeDepth-First SearchBreadth-First SearchBinary Tree | Medium | 53% | 67.4% | ||
| #148 | Sort List Linked ListTwo PointersDivide and ConquerSortingMerge Sort | Medium | 51% | 64.8% | ||
| #445 | Add Two Numbers II Linked ListMathStack | Medium | 50% | 62.8% | ||
| #2074 | Reverse Nodes in Even Length Groups Linked List | Medium | 88% | 64.7% | ||
| #430 | Flatten a Multilevel Doubly Linked List Linked ListDepth-First SearchDoubly-Linked List | Medium | 79% | 63.1% | ||
| #117 | Populating Next Right Pointers in Each Node II Linked ListTreeDepth-First SearchBreadth-First SearchBinary Tree | Medium | 50% | 57.8% | ||
| #2095 | Delete the Middle Node of a Linked List Linked ListTwo Pointers | Medium | 38% | 60.9% | ||
| #2058 | Medium | 100% | 69.5% | |||
| #2130 | Maximum Twin Sum of a Linked List Linked ListTwo PointersStack | Medium | 76% | 83.3% | ||
| #1171 | Remove Zero Sum Consecutive Nodes from Linked List Hash TableLinked List | Medium | 59% | 53.2% | ||
| #1721 | Swapping Nodes in a Linked List Linked ListTwo Pointers | Medium | 38% | 69.6% | ||
| #707 | Design Linked List Linked ListDesign | Medium | 31% | 30.5% | ||
| #1367 | Linked List in Binary Tree Linked ListTreeDepth-First SearchBinary Tree | Medium | 100% | 52.0% | ||
| #2181 | Merge Nodes in Between Zeros Linked ListSimulation | Medium | 63% | 89.7% | ||
| #1019 | Next Greater Node In Linked List ArrayLinked ListStackMonotonic Stack | Medium | 58% | 0.6% | ||
| #641 | Design Circular Deque ArrayLinked ListDesignQueue | Medium | 50% | 64.8% |
Browse company-specific interview problem lists and recency breakdowns:
Master core algorithmic patterns tested in FAANG & Big Tech coding interviews.
Reversing, reordering, and partitioning pointer chains with O(1) space It is categorized under Fundamentals and features 71 curated interview problems across Easy (11), Medium (52), and Hard (8) difficulties.
Companies frequently asking Linked List In-Place Manipulation questions include Amazon, Google, Microsoft, Meta, Bloomberg, Oracle.
Start by studying the algorithmic strategy and template code, then practice Easy and Medium problems before attempting Hard problems under timed conditions.