// clang++ -std=c++23 -Wall -Wextra -pedantic -D_CRT_SECURE_NO_WARNINGS elimination_simulation.cpp -g -o elimination_simulation.exe
// .\elimination_simulation.exe 7 1000000

#include <algorithm>
#include <iostream>
#include <numeric>
#include <random>
#include <vector>

int simulateRps(int n, std::mt19937 &gen) {
    std::uniform_int_distribution<> rps(0, 2);

    int rounds = 0;
    while (n > 1) {
        int cnts[3] = {};
        for (int i = 0; i < n; ++i) {
            ++cnts[rps(gen)];
        }

        // Some players are eliminated iff
        // there are exactly 2 different choices present.
        if ((cnts[0] > 0) + (cnts[1] > 0) + (cnts[2] > 0) == 2) {
            if (cnts[0] == 0) {
                // no rocks => scissors stay
                n = cnts[2];
            } else if (cnts[1] == 0) {
                // no papers => rocks stay
                n = cnts[0];
            } else {
                // no scissors => papers stay
                n = cnts[1];
            }
        }

        ++rounds;
    }

    return rounds;
}

int simulateZzz(int n, std::mt19937 &gen) {
    std::uniform_int_distribution<> rps(0, 1);

    int rounds = 0;
    while (n > 2) {
        int cnts[2] = {};
        for (int i = 0; i < n; ++i) {
            ++cnts[rps(gen)];
        }

        // Some players will be eliminated,
        // unless everyone chose the same or it's a tie.
        if (cnts[0] > 0 && cnts[1] > 0 && cnts[0] != cnts[1]) {
            // The minority stays.
            n = std::min(cnts[0], cnts[1]);
        }

        ++rounds;
    }

    // If 2 players remain, they play rock paper scissors.
    if (n == 2) {
        rounds += simulateRps(2, gen);
    }

    return rounds;
}

std::vector<int> runSimulationsRps(int n, int s, std::mt19937 &gen) {
    std::vector<int> rounds(s);
    for (int i = 0; i < s; ++i) {
        rounds[i] = simulateRps(n, gen);
    }

    std::sort(rounds.begin(), rounds.end());

    return rounds;
}

std::vector<int> runSimulationsZzz(int n, int s, std::mt19937 &gen) {
    std::vector<int> rounds(s);
    for (int i = 0; i < s; ++i) {
        rounds[i] = simulateZzz(n, gen);
    }

    std::sort(rounds.begin(), rounds.end());

    return rounds;
}

double getPercentile(const std::vector<int> &v, int p) {
    double r = p / 100.0;
    return std::lerp(
        v[std::floor(r * v.size())],
        v[std::ceil(r * v.size())],
        r * v.size() - std::floor(r * v.size())
    );
}

void printResults(const std::vector<int> &rounds) {
    int s = rounds.size();

    double avg = (double)std::reduce(rounds.begin(), rounds.end()) / s;

    int min = *std::min_element(rounds.begin(), rounds.end());
    int max = *std::max_element(rounds.begin(), rounds.end());

    double p50 = getPercentile(rounds, 50);
    double p90 = getPercentile(rounds, 90);
    double p95 = getPercentile(rounds, 95);
    double p99 = getPercentile(rounds, 99);

    std::cout << "avg=" << avg << std::endl;
    std::cout << "min=" << min << std::endl;
    std::cout << "p50=" << p50 << std::endl;
    std::cout << "p90=" << p90 << std::endl;
    std::cout << "p95=" << p95 << std::endl;
    std::cout << "p99=" << p99 << std::endl;
    std::cout << "max=" << max << std::endl;
}

int main(int argc, char *argv[]) {
    if (argc != 3) return 1;

    int n;
    if (std::sscanf(argv[1], "%d", &n) != 1) return 1;
    if (n < 1) return 1;

    int s;
    if (std::sscanf(argv[2], "%d", &s) != 1) return 1;
    if (s < 1) return 1;

    std::random_device rd;
    std::mt19937 gen(rd());

    std::cout << "ROCK PAPER SCISSORS" << std::endl;
    std::cout << "===================" << std::endl;
    printResults(runSimulationsRps(n, s, gen));
    std::cout << std::endl;

    std::cout << "ZIMI ZAMI ZUM" << std::endl;
    std::cout << "=============" << std::endl;
    printResults(runSimulationsZzz(n, s, gen));

    return 0;
}