Submission #679322

#	Time	Username	Problem	Language	Result	Execution time	Memory
679322		That_Salamander	Counting Mushrooms (IOI20_mushrooms)	C++14	56.64 / 100	11 ms	312 KiB

mushrooms

#include <bits/stdc++.h>

#include <cstdarg>
#include <cstdio>
#include <cstdlib>
#include <string>

using namespace std;

int use_machine(std::vector<int> x);

/*
250 => 55.2567
200 => 56.6416
150 => 54.067
*/
#define PREGEN 200

int count_mushrooms(int n) {
    vector<int> as = {0}, bs;

    int i;
    for (i = 1; i < PREGEN && i < n; i++) {
        if (use_machine({0, i})) {
            bs.push_back(i);
        } else {
            as.push_back(i);
        }
    }

    vector<int> use = as;
    bool swapped = false;

    if (bs.size() > as.size()) {
        use = bs;
        swapped = true;
    }

    int m = use.size() - 1;
    int count = as.size();

    while (i < n) {
        int process = min(m, n - i);

        vector<int> machine(process * 2 + 1);
        for (int j = 0; j <= process; j++) {
            machine[j * 2] = use[j];
        }

        for (int j = 0; j < process; j++) {
            machine[j * 2 + 1] = i + j;
        }

        int res = use_machine(machine) / 2;
        if (!swapped) {
            res = process - res;
        }

        count += res;
        i += process;
    }

    return count;
}


















#ifdef LOCAL_TEST
#include <random>
#include <time.h>
static char fmt_buffer[100000];
#define FMT_TO_STR(fmt, result)                            \
    va_list vargs;                                         \
    va_start(vargs, fmt);                                  \
    vsnprintf(fmt_buffer, sizeof(fmt_buffer), fmt, vargs); \
    va_end(vargs);                                         \
    fmt_buffer[sizeof(fmt_buffer) - 1] = 0;                \
    std::string result(fmt_buffer);

static const int min_n = 2;
static const int max_n = 20000;
static const int max_qc = 20000;
static const int max_qs = 100000;
static const int species_A = 0;
static const int species_B = 1;

static int n;
static std::vector<int> species;
static int qc, qs;

static inline void error_if(bool cond, std::string message) {
    if (cond) {
        printf("%s\n", message.c_str());
        exit(0);
    }
}

static inline void wrong_if(bool cond, std::string message) {
    error_if(cond, "Wrong Answer: " + message);
}

int use_machine(std::vector<int> x) {
    const int xs = x.size();
    wrong_if(xs < 2, "Too small array for query.");
    wrong_if(xs > n, "Too large array for query.");
    qc++;
    wrong_if(qc > max_qc, "Too many queries.");
    qs += xs;
    wrong_if(qs > max_qs, "Too many total array sizes as queries.");
    for (int i = 0; i < xs; i++)
        wrong_if(x[i] < 0 || n - 1 < x[i], "Invalid value in the query array.");
    std::vector<bool> used(n, false);
    for (int i = 0; i < xs; i++) {
        if (used[x[i]]) {
            cout << "Duplicate value in the query array." << endl;
            exit(0);
        }
        used[x[i]] = true;
    }
    int diffs = 0;
    for (int i = 1; i < xs; i++)
        diffs += int(species[x[i]] != species[x[i - 1]]);
    return diffs;
}

#ifdef __GNUC__
__attribute__((format(printf, 2, 3)))
#endif
static inline void
check_input(bool cond, const char* message_fmt, ...) {
    FMT_TO_STR(message_fmt, message);
    error_if(!cond, "Invalid input: " + message);
}

void createRandom() {
    n = 20000;
    species.resize(n);
    for (int& x : species) x = rand() % 2;
    species[0] = 0;
}

int main() {
    /*check_input(1 == scanf("%d", &n), "Could not read n.");
    check_input(min_n <= n, "n must not be less than %d, but it is %d.", min_n, n);
    check_input(n <= max_n, "n must not be greater than %d, but it is %d.", max_n, n);
    species.resize(n);
    for (int i = 0; i < n; i++) {
            check_input(1 == scanf("%d", &species[i]), "Could not read species element [%d].", i);
            check_input(species[i]==species_A || species[i] == species_B,
                                    "Species elements must be %d or %d, but species element [%d] is %d.", species_A, species_B, i, species[i]);
    }
    check_input(species[0] == species_A, "Species element [%d] must be %d.", 0, species_A);
    // Postponed closing standard input in order to allow interactive usage of the grader.
*/

    float best = 100.0;
    float longest = 0.0;
    for (int i = 0; i < 1000; i++) {
        createRandom();
        qc = 0;
        qs = 0;

        auto start = clock();
        int answer = count_mushrooms(n);
        auto end = clock();

        int actual = 0;
        for (int x: species) if(!x) actual++;

        float score;
        if (actual != answer) {
            cout << "WRONG ANSWER!" << endl;
            score = 0;
        } else if (qc > 20000) {
            score = 0;
        } else if (qc > 10010) {
            score = 10;
        } else if (qc > 904) {
            score = 25;
        } else if (qc > 226) {
            score = 226.0 / qc * 100.0;
        } else {
            score = 100;
        }

        //cout << "Score: " << score << " Guesses = " << qc << " Execution Time = " << (int) (((end - start) / (float) CLOCKS_PER_SEC) * 1000000) << " us" << endl;
        longest = max(longest, ((end - start) / (float) CLOCKS_PER_SEC));
        best = min(score, best);
    }

    cout << "Final Score: " << best << endl;
    cout << "Max Time: " << longest << " s" << endl;
}
#endif

• Subtask 1: 56.6416 / 100