Linked Lists Structures, Operations, and Types in Data Structures Practice Test

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• In an LRU cache implemented with a hashmap and a doubly linked list, what is the meaning of the head and tail in the recency order?
• If you call clear() on an empty list, what happens?
• What is the primary benefit of using a dummy head in a singly linked list?
• To detect the intersection node by reference when two singly linked lists have different lengths, which sequence of steps is correct?
• In what scenarios is a circular linked list particularly well-suited, and why?
• How do you traverse a singly linked list to print all node values, and what is the time complexity?
• What is the space complexity of reversing a singly linked list recursively (excluding input storage)?
• In a circular doubly linked list without a sentinel, which statement is true?
• What is the difference between begin() and end() methods?
• Provide an outline for reversing a singly linked list iteratively.
• During a sorted insertion algorithm, which pointer tracks the node just before the current node?
• Describe intrusive (embedded) linked lists in C, and typical usage pattern.
• How do you remove duplicates from a sorted singly linked list?
• How do you merge two sorted singly linked lists into a new sorted list using a dummy head and existing nodes?
• An STL-like feature for LList would include?
• During a sorted insertion algorithm for an ordered linked list, which pointer is used to traverse the list?
• How is a node typically declared in C++?
• To delete the nth node from the end of a singly linked list in one pass, which technique is described?
• If a list is empty, which statement about front() and back() is true?
• Which of the following correctly states the complexity of Floyd’s cycle detection algorithm and reporting the cycle length?
• What does the operator--() do in a doubly linked list iterator?
• Which statement best describes the data stored in each Node of the LList?
• In a singly linked list, which approach finds the i-th node from the end in a single pass?
• What is the difference between a stable and unstable merge of two lists, and which operations preserve stability?
• Outline a method to concatenate two singly linked lists without allocating new nodes.
• What is the time complexity of insertFirst() in an unordered linked list?
• What is a doubly linked list?
• In a sorted singly linked list, how can duplicates be removed in O(n) time and O(1) space?
• What is one clear advantage of maintaining a tail pointer when appending to a linked list?
• What is the initial state of a linked list when no nodes are present?
• Which method guarantees a new reversed list without mutating the original by constructing new nodes during traversal?
• In a traversal loop, what condition typically signals the end of the list?
• Which of the following describes the Node's connectivity in a doubly linked list?
• How can you remove a cycle from a linked list once you know the cycle's start node?
• What is the efficient way to delete the tail node of a doubly linked list when a tail pointer is maintained?
• What is the purpose of the copy constructor in a linked list?
• How would you sort a linked list using merge sort, and what is the time complexity?
• What is the output of the traversal algorithm for a linked list?
• What is the role of the Node structure within the LList class?
• Which of the following statements about memory deallocation is most appropriate when removing nodes?
• In a doubly linked list, what pointers exist in each node?
• If you only have access to a head pointer, removing the last element requires traversing to which node?
• What is the algorithm for sorted insertion in an ordered linked list?
• What is the time complexity and auxiliary space complexity of reversing a singly linked list iteratively?
• In C, intrusive or embedded linked lists embed the list pointers inside the user data structure, typically used for what purpose?
• Inserting a new node after a given node in a doubly linked list requires updating several pointers. Which option correctly performs this insertion after the given node?
• If a linked list is empty and you insert a new node at the head, what are the head and tail pointers after the operation?
• What is a recommended step to restore the original list after checking for palindrome by reversing the second half?
• Explain the recursive method to reverse a singly linked list and the base/recursive steps.
• What is the space complexity of a recursive reverse of a linked list?
• What is the time complexity of appending a node to the end of a singly linked list when a tail pointer is maintained?
• What is the purpose of the swap() method in the LList class?
• What are the two pointers used in the sorted insertion algorithm?
• What is the time complexity of accessing the i-th element in a singly linked list?
• What does the operator++() do in a linked list iterator?
• How can you compute the length of a singly linked list in a single pass?
• How would you convert a singly linked list into a circular linked list?
• In merging two sorted lists in place, what is the technique used?
• Which statement best describes the role of a node's link field in a singly linked list?
• Describe how to rotate a singly linked list to the right by k places.
• Which statement best describes inserting into an unordered linked list?
• Which data structure aids simplicity when deleting the nth node from the end of a singly linked list in one pass?
• What is the difference between a sentinel node and a dummy node, and how do they simplify algorithms?
• What is the time complexity of the copy constructor in the LList class?
• How do you initialize a linked list?
• Which scenario is most naturally modeled by a circular singly linked list?
• To support removal of the last returned element for a singly linked list, which approach is correct?
• What is the purpose of the link in a node?
• Why do doubly linked lists enable faster deletions compared to singly linked lists?
• How would you delete the head node of a singly linked list, and what is the time complexity?
• Which statement correctly captures the role of Node in LList?
• If you are given only a reference to a node (not the head) and you know it is not the tail, how can you delete that node?
• Which method finds the middle element of a singly linked list in one pass?
• What is the high-level approach for reversing a singly linked list recursively?
• In a doubly linked list, what is the time complexity of deleteNode if you already have a pointer to the node to delete?
• What is the time complexity of pop_back() if only a head pointer is available?
• How do you remove duplicates from an unsorted singly linked list without extra storage?
• How does a doubly linked list differ from a singly linked list in terms of per-node pointers and memory usage?
• How would you rotate a singly linked list to the right by k positions in place?
• How would you split a circular linked list into two equal halves?
• If two singly linked lists intersect by reference, what can be inferred about their tails?
• When reversing a singly linked list recursively, what is a typical base case?
• Explain how to implement a basic iterator for a singly linked list.
• Which operation on a singly linked list is guaranteed to be O(1) only when a tail pointer is maintained?
• Compare the dynamic resizing behavior of arrays vs linked lists.
• What are the time and space complexities of Floyd’s cycle detection algorithm?
• What is the time complexity of inserting a new node at the head of a circular singly linked list with a tail pointer, assuming the list is non-empty?
• What pointer is typically maintained to efficiently delete a node by value during a traversal?
• In the context of LList, front() provides access to which element?
• What does the length() function return in a linked list?
• In the typical singly linked list node declaration in C++, what is the type of the link member?
• How can you safely traverse and print a circular linked list without risking an infinite loop?
• What is the time complexity of inserting a new node at the head of a singly linked list?
• How do you insert a new node after a given node in a doubly linked list?
• Which algorithm detects cycles in a linked list with O(1) extra space?
• What does the front() function do in a linked list?
• Which operation would you use to determine if a particular value exists in a linked list?
• After deleting all nodes containing the target value, what will head.next reference?
• What does the insertion code p->link = new nodeType{50, p->link}; accomplish?
• What is the difference between an intrusive and a non-intrusive linked list?
• How do you find the kth node from the end of a singly linked list in one pass?
• In a doubly linked list, what is the time complexity of deleteNode when you must search for the item to delete?
• What is the space complexity of a top-down merge sort on a linked list due to recursion?
• What is the typical structure of a node in a singly linked list, and how does memory layout differ from an array?
• What is the difference between building a linked list forward and backward?
• What does the clear() method do in the LList class?
• What is the time complexity to split a circular linked list into two equal halves?
• Explain the algorithm to reverse a linked list in groups of k nodes.
• In sorting linked lists, what does stability mean, and is merge sort stable for linked lists?
• Define the intersection of two singly linked lists and describe a standard approach to detect it.
• What does the max_size() method define in the LList class?
• What is a linked list best described as?
• In a doubly linked list, which operation is typically easier to implement efficiently than in a singly linked list?
• How can pointer aliasing cause bugs in linked list insertions and deletions, and how can you mitigate it?
• Which statement is true about a circular singly linked list?
• To move from a node toward the previous node in a doubly linked list, which pointer do you follow?
• How would you check if a singly linked list is a palindrome with O(1) extra space?
• How would you determine whether two singly linked lists intersect by reference, and how would you locate the intersection node?
• How do you remove duplicates from an unsorted singly linked list with extra storage?
• In a circular singly linked list with a tail pointer, what does tail.next reference?
• What is a threaded linked list and what advantage does threading provide?
• What is the standard approach to delete all nodes containing a given value from a singly linked list, including edge cases?
• What is the expected time complexity to search for an element in a skip list compared to a standard singly linked list?
• Which statement best describes the cost of dynamic array resizing compared to linked list growth?
• During deletion, after identifying the node to delete and its predecessor, what is the next step?
• What is a primary memory-related advantage of using a singly linked list over an array?
• What does the link of the last node typically point to?
• How would you implement a memory-efficient queue using a singly linked list with head and tail pointers, and what are the time complexities of enqueue and dequeue?
• If the node to delete is known, what operation becomes possible in constant time?
• Two singly linked lists intersect by reference if and only if which condition holds?
• What does the operator*() do in a linked list iterator?
• What is the main difference between unordered and ordered linked lists?
• Which of the following is NOT listed among the core operations of a linked list ADT?
• Explain how to delete a node from a doubly linked list given a pointer to that node.
• Which describes the classic approach to check if a singly linked list is a palindrome using a stack?
• What is the time complexity of pop_front() in a linked list?
• What is the standard approach to inserting at the tail when no tail pointer exists?
• When calling front(), which precondition must be satisfied?
• What does the back() function do in a linked list?
• Why is a dummy head often used when reversing a list in groups of k nodes?
• What does the empty() method return?
• What is the effect of maintaining a tail pointer on the amortized cost of append operations when the list is used as a queue?
• Which description correctly outlines the k-group reversal for a singly linked list?
• What is a circular doubly linked list and what is a common use-case?
• Which statement best describes an advantage of linked lists over arrays?
• How would you implement a queue using a singly linked list with head and tail pointers?
• Which statement describes an intrusive linked list?
• Which operation returns the number of nodes currently in the list?
• After a cycle is detected, how can you find the start node of the cycle?
• A deep-copy copy constructor creates a new list that
• In a doubly linked list, removing a middle node requires updating which pointers?
• After inserting a node at the end of a circular singly linked list using a tail pointer, which statement is true about the tail pointer?
• If you want to check whether a list has no elements, which method would you use?
• What is the result of inserting nodes with values 2, 15, 8, 24, 34 at the head?
• How do you delete a node from a doubly linked list given only a pointer to that node?
• If a list contains N nodes, what does the length() function return?
• Compared to an O(1) space palindrome check, what is the space complexity of the stack-based approach?
• During insertion, after creating the new node and setting its data, what must you do next?
• What is a sentinel (dummy) node and why is it used in linked list algorithms?
• What is the purpose of iterators in linked lists?
• How would you remove duplicates from an unsorted linked list in O(n) time using extra space?
• Which approach is commonly used to merge two sorted singly linked lists into a single sorted list?
• Inserting at the head of a singly linked list with a dummy node at the head simplifies which scenario?
• What are the worst-case, average-case, and best-case time complexities for searching a value in an unsorted singly linked list?
• Why can't you delete a node in a singly linked list if you are given only a pointer to that node, and not to its predecessor?
• Given the head pointer and a value to delete, what is the standard procedure?
• What is the time complexity of insertBack() in a doubly linked list?
• In a singly linked list that uses a dummy head, how would you detect whether the list is empty?
• What is the defining feature of a threaded linked list that enables traversal without recursion?
• Why do you align two lists by length before checking for intersection by reference?
• When inserting a node at a specific index in a singly linked list, what is the typical approach and its time complexity?
• When reversing a block of k nodes in a singly linked list, what happens to the order of nodes within that block?
• What is a key property of circular linked lists that differentiates them from linear linked lists?
• What is a circular linked list and how does it differ from a standard singly linked list?
• What is the time complexity of inserting a node at an arbitrary index in a singly linked list, and why?
• Which statement about iterators and traversal is true?
• What does push_front() method do in the LList class?
• What does erase(iterator pos) method do in the LList class?
• What are the primary components of a linked list node?
• After performing an iterative reversal, what should you assign to head?
• What is the algorithm for traversing a linked list?
• What is the purpose of the head pointer?
• What is a typical trade-off of using a skip list compared to a balanced binary search tree?
• What is the difference between a singly linked list and a doubly linked list in terms of node pointers and traversal efficiency?
• What is the difference between NULL termination and a cycle in a linked list, and how would you test for each?
• If you need to delete a specific item by value in a doubly linked list and you must locate it first, what is the expected time complexity?
• What does a copy constructor guarantee when performing a deep copy of a linked list?
• What is the time complexity of reversing a singly linked list iteratively?
• What is the time complexity to locate the intersection node of two singly linked lists using a length-alignment approach (assuming they intersect)?
• What problems are associated with arrays?
• How would you implement a function that returns a new reversed list without modifying the original list?
• How do you insert a node at the end of a circular singly linked list given a tail pointer?
• How would you split a singly linked list into two lists containing nodes at odd and even positions, respectively?
• What is the process to insert a new node in a linked list?
• What is the effect of deleting a node in a linked list?
• What is the primary memory-related advantage of a doubly linked list over a singly linked list?
• Which sequence correctly reverses a singly linked list iteratively?
• Describe how to implement a 'split list' operation that divides a list into two halves.
• How can you check if a singly linked list is a palindrome without using extra data structures?
• Which of the following describes the end condition of a linear traversal of a linked list?
• What is the role of the tail pointer in a linked list?
• What is a common pattern for deletion in a linked list?
• Which statement best describes how termination and traversal differ between a singly linked list and a circular singly linked list?
• In a skip list, how is the height of each node determined?
• Which algorithm is used to detect a cycle in a singly linked list and to report the cycle length once detected?
• How do you detect a cycle in a linked list and what is the time/space complexity?
• When inserting into an empty circular singly linked list using the tail pointer, what should the new node's next pointer be set to?
• What is the time and space complexity of reversing a singly linked list in groups of k?
• Which data structure combination yields O(1) time for get and put operations in an LRU cache?
• How is the maximum size of the list conceptually defined in LList?
• Describe an in-place reversal of a doubly linked list and why it's simpler than reversing a singly linked list.
• How would you implement a function to remove the last node from a singly linked list with a tail pointer?
• What is the significance of the link pointer in a linked list?
• What is the trade-off of using a dummy node versus not using one in insertion at the head?
• How do you link two nodes in a linked list?
• Which components are typically included in a standard linkedListType class?
• Explain the amortized cost difference between appending to a linked list with a tail pointer vs appending to a dynamic array that occasionally resizes.
• How do you detect and measure the length of a cycle once detected in a linked list?
• What is the purpose of the LList class in the custom doubly linked list implementation?
• Which statement correctly describes inserting at the tail when a tail pointer is available?
• Explain the concept of a dummy head in a singly linked list and show a typical pattern where it simplifies code.
• Explain why a linked list is not suitable for random access by index in O(1), and what structure could provide fast random access.
• Describe a skip list and how it relates to linked lists.
• What is the primary purpose of the Node structure in a doubly linked list?
• Explain how to find the middle node of a singly linked list in one pass.
• What is the purpose of the destructor of a linked list?
• In the node declaration example, which member stores the actual data held by a node?
• What is the purpose of a count variable in a linked list?
• What is the difference between a 'head' pointer and a 'tail' pointer? How do they affect operations?
• How do you delete a node with a given value from a singly linked list when you have access to the head pointer?
• What does the front() method return in the LList class?
• How do you reverse a doubly linked list in place?
• When inserting a new node at the head of a circular singly linked list with a tail pointer, which sequence is correct?
• What happens when you insert a node at the head of a linked list?
• Edge-case handling when deleting nodes at the head of a singly linked list: how does a dummy head affect the process?