for_each

oster_man

Aug 19th, 2023

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#include <algorithm>
#include <execution>
#include <iostream>
#include <list>
#include <random>
#include <string>
#include <string_view>
#include <type_traits>
#include <vector>
#include <future>
#include "log_duration.h"
using namespace std;
string GenerateWord(mt19937& generator, int max_length) {
const int length = uniform_int_distribution(1, max_length)(generator);
string word;
word.reserve(length);
for (int i = 0; i < length; ++i) {
word.push_back(uniform_int_distribution('a', 'z')(generator));
}
return word;
}
template <template <typename> typename Container>
Container<string> GenerateDictionary(mt19937& generator, int word_count, int max_length) {
vector<string> words;
words.reserve(word_count);
for (int i = 0; i < word_count; ++i) {
words.push_back(GenerateWord(generator, max_length));
}
return Container(words.begin(), words.end());
}
struct Reverser {
void operator()(string& value) const {
reverse(value.begin(), value.end());
}
};
template <typename Container, typename Function>
void Test(string_view mark, Container keys, Function function) {
LOG_DURATION(mark);
function(keys, Reverser{});
}
#define TEST(function) Test(#function, keys, function<remove_const_t<decltype(keys)>, Reverser>)
template <typename ForwardRange, typename Function>
void ForEach(ForwardRange& range, Function function) {
// ускорьте эту реализацию
int AsyncPart=20000;
if (!range.empty()){
int divisions = range.size()/AsyncPart;
if (!divisions){
for_each(range.begin(),range.end(),function);
}
else{
auto first = range.begin(); //0
auto last = range.begin(); //0
last = next(first,range.size()/divisions); //0 + size/divisions
vector<future<void>> futures;
for(int i=0;i<divisions;++i){
futures.push_back(async([first,last,function]{
for_each(first,last,function);
}));
first = next(last);
advance(first,range.size()/divisions);
}
for_each(futures.begin(),futures.end(),[](auto& asyncFunc){
asyncFunc.get();
});
}
}
//for_each(execution::par,range.begin(),range.end(),function);
}
int main() {
// для итераторов с произвольным доступом тоже должно работать
vector<string> strings = {"cat", "dog", "code"};
ForEach(strings, [](string& s) {
reverse(s.begin(), s.end());
});
for (string_view s : strings) {
cout << s << " ";
}
cout << endl;
// вывод: tac god edoc
mt19937 generator;
const auto keys = GenerateDictionary<list>(generator, 50'000, 5'000);
TEST(ForEach);
return 0;
}

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