Submission #308524

#	Time	Username	Problem	Language	Result	Execution time	Memory
308524		CodePlatina	Counting Mushrooms (IOI20_mushrooms)	C++14	100 / 100	11 ms	576 KiB

mushrooms

#include "mushrooms.h"
#include <vector>

using namespace std;

const int K = 100;

int count_mushrooms(int n)
{
    if(n <= 453)
    {
        int ret = 1;
        for(int i = 1; i < n; i += 2)
        {
            if(i == n - 1) ret += 1 - use_machine({0, i});
            else ret += 2 - use_machine({i, 0, i + 1});
        }
        return ret;
    }
    else
    {
        int ret = 0;
        vector<int> A, B, C, D, E;
        A.push_back(0);
        for(int i = 1; i < n; ++i) C.push_back(i);
        while(A.size() < K && B.size() < K && A.size() + B.size() + D.size() < 2 * K - 1)
        {
            if(A.size() >= 3)
            {
                int x = C.back(); C.pop_back();
                int y = C.back(); C.pop_back();
                int z = C.back(); C.pop_back();
                int t = use_machine({A[0], x, A[1], y, A[2], z});
                if(t & 1) B.push_back(z);
                else A.push_back(z);
                if(t / 2 == 0) A.push_back(x), A.push_back(y);
                else if(t / 2 == 2) B.push_back(x), B.push_back(y);
                else if(B.size() >= 2)
                {
                    int u = C.back(); C.pop_back();
                    int v = C.back(); C.pop_back();
                    t = use_machine({B[0], x, B[1], A[0], y, A[1], u, A[2], v}) - 1;
                    if(t & 1) B.push_back(v);
                    else A.push_back(v);
                    if(t >> 1 & 1) B.push_back(u);
                    else A.push_back(u);
                    if(t >> 2) A.push_back(x), B.push_back(y);
                    else B.push_back(x), A.push_back(y);
                }
                else
                {
                    D.push_back(x);
                    E.push_back(y);
                }
            }
            else if(B.size() >= 3)
            {
                int x = C.back(); C.pop_back();
                int y = C.back(); C.pop_back();
                int z = C.back(); C.pop_back();
                int t = use_machine({B[0], x, B[1], y, B[2], z});
                if(t & 1) A.push_back(z);
                else B.push_back(z);
                if(t / 2 == 0) B.push_back(x), B.push_back(y);
                else if(t / 2 == 2) A.push_back(x), A.push_back(y);
                else if(A.size() >= 2)
                {
                    int u = C.back(); C.pop_back();
                    int v = C.back(); C.pop_back();
                    t = use_machine({A[0], x, A[1], B[0], y, B[1], u, B[2], v}) - 1;
                    if(t & 1) A.push_back(v);
                    else B.push_back(v);
                    if(t >> 1 & 1) A.push_back(u);
                    else B.push_back(u);
                    if(t >> 2) B.push_back(x), A.push_back(y);
                    else A.push_back(x), B.push_back(y);
                }
                else
                {
                    D.push_back(x);
                    E.push_back(y);
                }
            }
            else if(A.size() >= 2)
            {
                int x = C.back(); C.pop_back();
                int y = C.back(); C.pop_back();
                int t = use_machine({A[0], x, A[1], y});
                if(t & 1) B.push_back(y);
                else A.push_back(y);
                if(t / 2) B.push_back(x);
                else A.push_back(x);
            }
            else if(B.size() >= 2)
            {
                int x = C.back(); C.pop_back();
                int y = C.back(); C.pop_back();
                int t = use_machine({B[0], x, B[1], y});
                if(t & 1) A.push_back(y);
                else B.push_back(y);
                if(t / 2) A.push_back(x);
                else B.push_back(x);
            }
            else
            {
                int x = C.back(); C.pop_back();
                int t = use_machine({A[0], x});
                if(t) B.push_back(x);
                else A.push_back(x);
            }
            if(D.size() == 2)
            {
                if(A.size() >= 2)
                {
                    int t = use_machine({A[0], D[0], A[1], D[1]});
                    if(t / 2) B.push_back(D[0]), A.push_back(E[0]);
                    else A.push_back(D[0]), B.push_back(E[0]);
                    if(t & 1) B.push_back(D[1]), A.push_back(E[1]);
                    else A.push_back(D[1]), B.push_back(E[1]);
                }
                else
                {
                    int t = use_machine({B[0], D[0], B[1], D[1]});
                    if(t / 2) A.push_back(D[0]), B.push_back(E[0]);
                    else B.push_back(D[0]), A.push_back(E[0]);
                    if(t & 1) A.push_back(D[1]), B.push_back(E[1]);
                    else B.push_back(D[1]), A.push_back(E[1]);
                }
                D.clear(); E.clear();
            }
        }
        if(D.size() == 1)
        {
            int x = C.back(); C.pop_back();
            int t = use_machine({A[0], x, A[1], D[0]});
            if(t & 1) B.push_back(D[0]), A.push_back(E[0]);
            else A.push_back(D[0]), B.push_back(E[0]);
            if(t / 2) B.push_back(x);
            else A.push_back(x);
        }
        while(C.size())
        {
            if(A.size() >= B.size())
            {
                int cnt = -1;
                vector<int> tmp;
                for(int i = 0; (int)C.size() && i < (int)A.size(); ++i)
                {
                    ++cnt;
                    tmp.push_back(A[i]);
                    tmp.push_back(C.back());
                    C.pop_back();
                }
                int t = use_machine(tmp);
                if(t & 1) --t, B.push_back(tmp.back());
                else A.push_back(tmp.back());
                ret += cnt - t / 2;
            }
            else
            {
                int cnt = -1;
                vector<int> tmp;
                for(int i = 0; (int)C.size() && i < (int)B.size(); ++i)
                {
                    ++cnt;
                    tmp.push_back(B[i]);
                    tmp.push_back(C.back());
                    C.pop_back();
                }
                int t = use_machine(tmp);
                if(t & 1) --t, A.push_back(tmp.back());
                else B.push_back(tmp.back());
                ret += t / 2;
            }
        }
        return ret + A.size();
    }
}

• Subtask 1: 100 / 100