Freaks City

Virtual functions form the foundation of runtime polymorphism in C++. This article explores how virtual functions work, the mechanics of the vtable, and special cases like covariance and destructor overriding. Virtual Functions Consider the following code and analyze the output: #include <iostream> using namespace std; class Base { publi ...

01 Knapsack Given N item types and a knapsack with capacity V. Each item can be selected at most once, with volume v[i] and value w[i]. Find the maximum total value without exceeding capacity. Constraints: 0 < N, V <= 1000; 0 < v[i], w[i] <= 1000. The classic 01 knapsack uses a two-state transition approach: either skip the current ...

Special Member Functions in C++ Special member functions are implicitly declared by the compiler when not explicitly defined by the user. For a typical class, the compiler generates six such functions: default constructor, destructor, copy constructor, copy assignment operator, address-of operator overloads (non-const and const), and — since C+ ...

N-ary Tree Preorder Traversal Given the root of an n-ary tree, return the preorder traversal of its nodes' values. /* class Node { public: int val; vector<Node*> children; Node() {} Node(int _val) { val = _val; } Node(int _val, vector<Node*> _children) { val = _val; children = _children; } }; ...

Optimizing Singly Linked Lists with a Tail Pointer In a standard singly linked list, inserting an element at the end requires traversing the entire list, resulting in an O(n) time complexity. To optimize this operation to O(1), we can introduce a tail pointer that always references the last node in the sequence. The structure remains a singly l ...

Two Pointers Two pointers is a fundamental technique that uses two references to traverse data structures simultaneously. There are two primary variants: Collision Pointers (Converging Pointers): Both pointers start from opposite ends and move toward each other. Fast and Slow Pointers: Both pointers move in the same direction but at different s ...

Exercise 1: Modern C++ Programming Basics Task 1: STL Algorithm Deomnstration - reverse, reverse_copy, rotate Source code: #include <bits/stdc++.h> using namespace std; // Template function declaration template<typename T> void printContainer(const T& container); // Regular function declarations void demoReverseOperations(); v ...

Creating Separator Lines QFrame* separator = new QFrame(); separator->setFrameShape(QFrame::HLine); separator->setFrameShadow(QFrame::Sunken); Making QLabel Resize to Text Content QLabel widget; widget.setText("content"); widget.adjustSize(); widget.setFixedWidth(widget.width()); widget.setFixedHeight(widget.height()); Adddin ...

Core Concepts Libraries organize related functionality into separate modules to achieve decoupling. Name spaces resolve conflicts from identically named functions across different libraries. C++ is fully backward compatible with C. All standard C++ components (classes, functions, variables) are placed in the std name space, so cout is fully qua ...

Task 1: Sequence Manipulation with Iterators This task demonstrates the manipulation of container elements using standard algorithms. We will explore how to reverse sequences and perform cyclic rotations on both strings and vectors. #include <iostream> #include <string> #include <vector> #include <algorithm> #include &lt ...