0_seq_and_parallel_speed_test

#include <algorithm>
#include <utility>
#include <execution>  // !!!
#include <vector>
#include <iostream>
#include <string_view>

#include "log_duration.h"

using namespace std;

struct Document {
    int id;
    double relevance;
    int rating;
};

void SortDocumentsDefault(vector<Document>& documents) {
    LOG_DURATION("default");
    sort(execution::seq, documents.begin(), documents.end(),
         [](const Document& lhs, const Document& rhs) {
             return pair<int, double>{lhs.rating, lhs.relevance}
                  > pair<int, double>{rhs.rating, rhs.relevance};
         });
}

void SortDocumentsParallel(vector<Document>& documents) {
    LOG_DURATION("parallel");
    sort(execution::par,  // !!!
         documents.begin(), documents.end(),
         [](const Document& lhs, const Document& rhs) {
             return pair<int, double>(lhs.rating, lhs.relevance)
                  > pair<int, double>(rhs.rating, rhs.relevance);
         });
}

int main() {
    vector<Document> docs1;
    vector<Document> docs2;

    docs1.reserve(10000000);
    docs2.reserve(10000000);

    for (int i = 0; i < 10; ++i) {
        for (int id = 0; id < 10000000; ++id) {
            docs1.push_back({id, 0.5, id});
            docs2.push_back({id, 0.5, id});
        }
    }

    SortDocumentsDefault(docs1);
    SortDocumentsParallel(docs2);
}