class B
{
  public: virtual void f() {};
};

class D : public B
{
  public: void f() override {};
};

void Func() {
    B* tmp = new D();
    tmp->f();
}




number -> email


import re
import os
import sys

str = '\+7([0-9]{3,3})[0-9]{7,7}'
email = ''

def GetDirs(path):


def GetFiles(path):


def Dfs(current_path, email, str):
    files = GetFiles(current_path);
    for file_name in files:
        s = open(file_name).read()
        while re.replace(str, s, email):
            pass
    folders = GetDirs(current_path)
    for folder in folders:
        new_path = current_path


find . -print0 -name '*html' | xargs -0 -n1 sed -i 's/regex/email/g'

uint8_t reverse(uint8_t in) {
    for (size_t i = 0; i < 4; ++i) {
        if ((in >> i) ^ (in >> (7 - i)) & 1) {
            in ^= 1 << i;
            in ^= 1 << (7 - i);
        }
    }
    return in;
}


rb-tree - std::set, std::map
std::queue<int> q;
q.push(x);
q.pop();
q.front();

list/vector/set/map/deques
std::array<T, N>
make_heap(st, en)
priority_queue<>

unordered_set<T>, unordered_map<T, T>



SegmentTree
FenwickTree
Trie
SuffixArray
SqrtDecomp
HeavyLightDecomp


template<T>
class Queue { // RAII
private:
    std::conditional_value c;
    std::queue<T&&> q;
    std::mutex m;

public:
    void Push(T&& x) {
        {
        std::lock_guard<std::mutex> guard(m);
        q.push(std::move(x));
        }
        c.notify_one();
    }

    T Pop() {
        std::lock_guard<std::mutex> guard(m);
        if (q.empty() )
        {
            c.wait([this] { return !q.empty(); });
        }
        T value = std::move(q.front());
        q.pop();
        return value;
    }


};