Explain C++ containers, segfaults, and virtual dispatch

Answer the following C++ conceptual questions:

1. C++ standard containers implementation
   For common C++ standard library containers such as std::vector , std::list , std::map , and std::unordered_map :
   • What are their typical underlying data structures and memory layouts?
   • What are their key performance characteristics (time complexity of insert, erase, random access, iteration)?
   • In what scenarios would you prefer one container over another?
2. Segmentation fault causes
   In C or C++, what is a segmentation fault, and in what typical situations can it occur?
   Give several concrete examples involving pointers, arrays, and memory management.
3. Virtual constructors in C++
   Can a constructor in C++ be declared as virtual ? Why or why not?
   Explain the language and object model reasons behind this, and mention common patterns used when people think they "need" a virtual constructor.
4. How virtual functions find the correct implementation
   How does C++ implement virtual function dispatch under the hood?
   Explain how the program decides at runtime which overridden function to call when you invoke a virtual method through a base-class pointer or reference.
   Include in your explanation:
   • The roles of the vtable and vptr (or equivalent mechanisms).
   • What happens with single inheritance vs. multiple inheritance at a high level.
   • Any special considerations during construction and destruction.