Insertion sort bench

insert_bench.cpp

#include<bits/stdc++.h>

void insertion_sort(std::vector<int> &a) {
    for (int i = 1; i < a.size(); i++) {
        int b = a[i];
        int j = i - 1;
        for (; j >= 0 && b < a[j]; j--) {
            a[j + 1] = a[j];
        }
        a[j + 1] = b;
    }
}

void insertion_sort_down(std::vector<int> &a) {
    for (int i = 1; i < a.size(); i++) {
        int b = a[i];
        int j = i - 1;
        for (; j >= 0 && b > a[j]; j--) {
            a[j + 1] = a[j];
        }
        a[j + 1] = b;
    }
}

void display(std::vector<int> &a) {
    for (int k : a) std::cout << k << ' ';
    std::cout << '\n';
}

int main() {
    std::vector<int> sizes {10, 100, 1000, 10000};

    std::cout << "size,random_time,bestcase,worstcase\n";
    for (int i : sizes) {
        std::vector<int> b(i);
        std::generate(b.begin(), b.end(), [](){ return std::rand() % 1000; });
        auto n1 = std::chrono::high_resolution_clock::now();
        insertion_sort(b);
        auto d = std::chrono::duration_cast<std::chrono::nanoseconds>(std::chrono::high_resolution_clock::now() - n1);
        n1 = std::chrono::high_resolution_clock::now();
        insertion_sort(b);
        auto d2 = std::chrono::duration_cast<std::chrono::nanoseconds>(std::chrono::high_resolution_clock::now() - n1);
        std::reverse(b.begin(), b.end());
        n1 = std::chrono::high_resolution_clock::now();
        insertion_sort(b);
        auto d3 = std::chrono::duration_cast<std::chrono::nanoseconds>(std::chrono::high_resolution_clock::now() - n1);

        std::cout << i << ',' << d.count() << ',' << d2.count() << ',' << d3.count() << '\n';
    }
}

odd_even_sort.cpp

#include<bits/stdc++.h>

void insertion_sort(std::vector<int> &a) {
    for (int i = 1; i < a.size(); i += 2) {
        int b = a[i];
        int j = i - 2;
        for (; j >= 0 && b < a[j]; j -= 2) {
            a[j + 2] = a[j];
        }
        a[j + 2] = b;
    }
}

void insertion_sort_down(std::vector<int> &a) {
    for (int i = 2; i < a.size(); i += 2) {
        int b = a[i];
        int j = i - 2;
        for (; j >= 0 && b > a[j]; j -= 2) {
            a[j + 2] = a[j];
        }
        a[j + 2] = b;
    }
}

void display(std::vector<int> &a) {
    for (int k : a) std::cout << k << ' ';
    std::cout << '\n';
}

int main() {
    std::vector<int> b(10);
    std::generate(b.begin(), b.end(), [](){ return std::rand() % 10; });

    display(b);
    insertion_sort(b);
    insertion_sort_down(b);
    display(b);
    return 0;
}