Submission #817699

#	Time	Username	Problem	Language	Result	Execution time	Memory
817699		math_rabbit_1028	Counting Mushrooms (IOI20_mushrooms)	C++14	0 / 100	11 ms	332 KiB

mushrooms

#include "mushrooms.h"
#include <bits/stdc++.h>
using namespace std;

int count_mushrooms(int n) {
    int b = sqrt(n/3);
    vector<int> Alist, Blist;
    Alist.push_back(0);
    int i, ans = Alist.size();

    if (n <= 200) {
        for (int i = 1; i < n; i++) if (use_machine({Alist[0], i}) == 0) ans++;
        return ans;
    }

    if (use_machine({0, 1}) == 0) {
        Alist.push_back(1);
        for (i = 2; i < n; i += 2) {
            int ret = use_machine({Alist[0], i, Alist[1], i + 1});
            if (ret >= 2) Blist.push_back(i);
            else Alist.push_back(i);
            if (ret % 2 == 0) Alist.push_back(i + 1);
            else Blist.push_back(i + 1);
            if (Alist.size() >= 3 && Blist.size() >= 3) break;
        }
    }
    else {
        Blist.push_back(1);
        if (use_machine({0, 2}) == 0) {
            Alist.push_back(2);
            for (i = 3; i < n; i += 2) {
                int ret = use_machine({Alist[0], i, Alist[1], i + 1});
                if (ret >= 2) Blist.push_back(i);
                else Alist.push_back(i);
                if (ret % 2 == 0) Alist.push_back(i + 1);
                else Blist.push_back(i + 1);
                if (Alist.size() >= 3 && Blist.size() >= 3) break;
            }
        }
        else {
            Blist.push_back(2);
            for (i = 3; i < n; i += 2) {
                int ret = use_machine({Blist[0], i, Blist[1], i + 1});
                if (ret >= 2) Alist.push_back(i);
                else Blist.push_back(i);
                if (ret % 2 == 0) Blist.push_back(i + 1);
                else Alist.push_back(i + 1);
                if (Alist.size() >= 3 && Blist.size() >= 3) break;
            }
        }
    }

    i += 2;
    for (; i < n; i += 5) {
        int ret = use_machine({Alist[0], i, Alist[1], i + 1, Alist[2], i + 2}), ret2;
        if (ret == 0) {
            Alist.push_back(i);
            Alist.push_back(i + 1);
            Alist.push_back(i + 2);
        }
        if (ret == 1) {
            Alist.push_back(i);
            Alist.push_back(i + 1);
            Blist.push_back(i + 2);
        }
        if (ret == 4) {
            Blist.push_back(i);
            Blist.push_back(i + 1);
            Alist.push_back(i + 2);
        }
        if (ret == 5) {
            Blist.push_back(i);
            Blist.push_back(i + 1);
            Blist.push_back(i + 2);
        }
        if (ret == 0 || ret == 1 || ret == 4 || ret == 5) {
            ret2 = use_machine({Alist[0], i + 3, Alist[1], i + 4});
        }

        if (ret == 2 || ret == 3) {
            ret2 = use_machine({Blist[0], i, Blist[1], Alist[0], i + 1, Alist[1], i + 3, Alist[2], i + 4}) - 1;
            if (ret2 >= 4) {
                Alist.push_back(i);
                Blist.push_back(i + 1);
            }
            else {
                Blist.push_back(i);
                Alist.push_back(i + 1);
            }
            Alist.push_back(i + 2);
            ret2 = ret2 % 4;
        }

        if (ret2 >= 2) Blist.push_back(i + 3);
        else Alist.push_back(i + 3);
        if (ret2 % 2 == 0) Alist.push_back(i + 4);
        else Blist.push_back(i + 4);

        if (Alist.size() >= b || Blist.size() >= b) break;
    }

    ans = Alist.size();
    i += 5;
    for (; i < n; ) {
        vector<int> seq;
        if (Alist.size() >= Blist.size()) {
            for (int j = i; j < min(i + (int)Alist.size(), n); j++) {
                seq.push_back(Alist[j - i]);
                seq.push_back(j);
            }
            int ret = use_machine(seq);
            ans += (min(i + (int)Alist.size(), n) - i) - (ret + 1) / 2;
            i += Alist.size();
            if (ret % 2 == 0) Alist.push_back(i - 1);
            if (ret % 2 == 1) Blist.push_back(i - 1);
        }
        else {
            for (int j = i; j < min(i + (int)Blist.size(), n); j++) {
                seq.push_back(Blist[j - i]);
                seq.push_back(j);
            }
            int ret = use_machine(seq);
            ans += (ret + 1) / 2;
            i += Blist.size();
            if (ret % 2 == 0) Blist.push_back(i - 1);
            if (ret % 2 == 1) Alist.push_back(i - 1);
        }
    }
    return ans;
}

Compilation message (stderr)

mushrooms.cpp: In function 'int count_mushrooms(int)':
mushrooms.cpp:99:26: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   99 |         if (Alist.size() >= b || Blist.size() >= b) break;
      |             ~~~~~~~~~~~~~^~~~
mushrooms.cpp:99:47: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   99 |         if (Alist.size() >= b || Blist.size() >= b) break;
      |                                  ~~~~~~~~~~~~~^~~~
mushrooms.cpp:96:22: warning: 'ret2' may be used uninitialized in this function [-Wmaybe-uninitialized]
   96 |         if (ret2 % 2 == 0) Alist.push_back(i + 4);
      |             ~~~~~~~~~^~~~

• Subtask 1: 0 / 100