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Questions and Answers
What is the primary distinguishing feature of a priority queue?
What is the primary distinguishing feature of a priority queue?
What is a common use case for a double-ended queue (deque)?
What is a common use case for a double-ended queue (deque)?
What is a key characteristic of a tree data structure?
What is a key characteristic of a tree data structure?
What is the main difference between stack and heap memory allocation in C++?
What is the main difference between stack and heap memory allocation in C++?
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What is the purpose of a priority queue in job scheduling?
What is the purpose of a priority queue in job scheduling?
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Which of the following is a common operation in a tree data structure?
Which of the following is a common operation in a tree data structure?
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What is the primary advantage of using heap memory allocation?
What is the primary advantage of using heap memory allocation?
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What is the advantage of using a deque over a regular queue?
What is the advantage of using a deque over a regular queue?
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What is a characteristic of objects and variables allocated on the heap?
What is a characteristic of objects and variables allocated on the heap?
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What is the significance of heap memory allocation in C++?
What is the significance of heap memory allocation in C++?
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What is a disadvantage of heap memory allocation?
What is a disadvantage of heap memory allocation?
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Why is heap memory allocation slower than stack allocation?
Why is heap memory allocation slower than stack allocation?
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What happens to memory allocated on the heap when it is no longer needed?
What happens to memory allocated on the heap when it is no longer needed?
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What is an example of a situation where heap memory allocation is particularly useful?
What is an example of a situation where heap memory allocation is particularly useful?
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What is a consequence of memory fragmentation on the heap?
What is a consequence of memory fragmentation on the heap?
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What is a limitation of the stack?
What is a limitation of the stack?
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Why is stack frame access easier than heap frame access?
Why is stack frame access easier than heap frame access?
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When should you allocate memory on the heap?
When should you allocate memory on the heap?
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What is the difference between stack and heap in terms of memory size allotment?
What is the difference between stack and heap in terms of memory size allotment?
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What happens when you use the new operator to allocate memory in C++?
What happens when you use the new operator to allocate memory in C++?
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What is the default state of the integer allocated on the heap using the new operator?
What is the default state of the integer allocated on the heap using the new operator?
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What is stored on the stack when you issue the command int *ptr = new int;
?
What is stored on the stack when you issue the command int *ptr = new int;
?
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Why is memory allocation on the heap not automatically managed?
Why is memory allocation on the heap not automatically managed?
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What is the main difference in terms of access time between the stack and the heap?
What is the main difference in terms of access time between the stack and the heap?
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What is the first step in the provided code for deleting an element by value?
What is the first step in the provided code for deleting an element by value?
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What happens if we don't have a destructor in the LinkedList class?
What happens if we don't have a destructor in the LinkedList class?
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What is the purpose of checking if the element to be deleted is located at the start of the linked list?
What is the purpose of checking if the element to be deleted is located at the start of the linked list?
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What is the function of the 'next' variable in the provided code?
What is the function of the 'next' variable in the provided code?
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What is the consequence of not deleting the node being pointed to by the 'temp' variable?
What is the consequence of not deleting the node being pointed to by the 'temp' variable?
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Why is dynamic memory allocation used to create nodes in the LinkedList class?
Why is dynamic memory allocation used to create nodes in the LinkedList class?
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What is the purpose of the increment function?
What is the purpose of the increment function?
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In the insert_before_node function, what happens if the element is found at the first node?
In the insert_before_node function, what happens if the element is found at the first node?
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What is the purpose of the temp variable in the insert_before_node function?
What is the purpose of the temp variable in the insert_before_node function?
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What happens if the element is not found in the linked list?
What happens if the element is not found in the linked list?
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How does the insert_before_node function insert a new node before a given node?
How does the insert_before_node function insert a new node before a given node?
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What is the condition for the while loop to stop executing in the insert_before_node function?
What is the condition for the while loop to stop executing in the insert_before_node function?
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What happens to the head node when a new node is inserted before it?
What happens to the head node when a new node is inserted before it?
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What is the purpose of the new_node variable in the insert_before_node function?
What is the purpose of the new_node variable in the insert_before_node function?
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Study Notes
Data Structures
- Priority Queue: a queue where each element has a priority, and elements are served based on their priority
- Used in scenarios where elements need to be processed based on their importance or urgency (e.g. job scheduling, event handling, graph algorithms like Dijkstra's shortest path algorithm)
- Double-ended Queue (Deque): a generalized version of a queue where elements can be inserted or removed from both ends
- Supports operations like push_front, push_back, pop_front, and pop_back
- Used in scenarios where elements need to be added or removed from both ends (e.g. sliding window algorithms, undo/redo operations, breadth-first search algorithms)
- Tree: a hierarchical data structure consisting of nodes connected by edges
- Has a root node, and each node can have zero or more child nodes
- Common operations include insertion, deletion, and traversal (pre-order, in-order, post-order)
- Used in scenarios where data needs to be organized hierarchically (e.g. file systems, decision trees, binary search trees, heaps)
Stack and Heap Memory Allocation
- Stack Allocation:
- Allocation happens on contiguous blocks of memory
- Memory size is known to the compiler, and memory is allocated on the stack when a function is called
- Stack frame access is easier and more cache-friendly compared to heap frames
- Stack is not flexible, and memory size cannot be changed
- Heap Allocation:
- Allocation happens on the heap when using the
new
operator - Memory allocated on the heap is not automatically managed and must be explicitly freed by the programmer using
delete
- Memory allocated on the heap remains allocated until explicitly de-allocated
- Useful for situations where the amount of memory required cannot be determined at compile time (e.g. handling user input, working with data structures like linked lists, managing large data sets)
- Allocation happens on the heap when using the
When to Use the Heap?
- Use the heap when:
- You need to allocate a large block of memory (e.g. a large array or big class) and keep it around for a long time
- You need to dynamically allocate memory for situations where the amount of memory required cannot be determined at compile time
- Use the stack when:
- You are dealing with relatively small variables that only need to persist as long as the function using them is alive
Disadvantages of Heap Memory
- Performance Overhead:
- Slower allocation and de-allocation compared to the stack
- Fragmentation can lead to inefficient memory usage and increased allocation times
- Fragmentation:
- Over time, the heap can become fragmented as blocks of memory are allocated and de-allocated in varying sizes
LinkedList Implementation
- Insertion:
- If the element after which we want to insert a new node is located at the first node of the list, we simply set the next variable of the newly inserted node to point to the head and then set the value of head as the new_node
- If the list is not NULL and the element is not found at the first node, we create a new pointer variable temp and assign the head variable to it
- We traverse through the linked list using a while loop until temp->next becomes NULL
- If the item is found, the temp->next variable will not be NULL
- Deletion:
- We first check if the list is empty
- If the element to be deleted is located at the start of the linked list, we delete it by setting the head to the next variable of the first node
- If the element is not found at the first index, we iterate through the linked list and check if the value of the node being iterated is equal to the value to be deleted
- If the comparison returns true, we set the next variable of the previous node to the node which exists after the node which is being deleted
- Destructor:
- Essential for proper memory management
- Without a destructor, the allocated memory for the nodes would not be freed, resulting in a memory leak
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Description
Learn about two essential data structures: Priority Queue and Double-ended Queue. Understand their applications and operations.