Submission #1195538

#	Time	Username	Problem	Language	Result	Execution time	Memory
1195538		tutis	Message (IOI24_message)	C++20	95 / 100	506 ms	864 KiB

message

#include "message.h"
#include <algorithm>
#include <chrono>
#include <iostream>
#include <random>
#include <bitset>
#include <vector>
#include <deque>
#include <assert.h>
#include <math.h>

using namespace std;

int counter = 0;

bitset<31> masks[200];
const int64_t seed1 = 5;
int tests = 10000;

bitset<31> globC;

bool initialized = false;

mt19937_64 rngSending(0);
bitset<31> send(bitset<31> A, bitset<31> C)
{
    if (counter >= 199)
    {
        assert(false);
    }
    A = A ^ masks[counter];
    vector<bool> Avector(31);
    for (int i = 0; i < 31; i++)
    {
        Avector[i] = A[i];
        if (C[i])
        {
            Avector[i] = rngSending() % 2;
        }
    }
    vector<bool> recVector = send_packet(Avector);
    bitset<31> received;
    for (int j = 0; j < 31; j++)
    {
        received[j] = recVector[j];
    }
    received = received ^ masks[counter];
    counter++;
    return received;
}

const int Q = 67;

deque<bool> prepareBits(vector<bool> M, bitset<31> C)
{
    deque<bool> X;
    mt19937_64 rng(C.to_ullong());
    for (int i = 0; i < 16 * Q - 27 - 1025; i++)
    {
        X.push_back(rng() % 2 == 1);
    }
    int offset = 1024 - M.size();
    for (int i = 0; i < offset; i++)
    {
        X.push_back(1);
    }
    X.push_back(0);
    for (int v : M)
    {
        X.push_back(v);
    }
    return X;
}

void init()
{
    counter = 0;
    if (!initialized)
    {
        mt19937_64 rng(seed1);
        for (int i = 0; i < 200; i++)
        {
            for (int j = 0; j < 31; j++)
            {
                masks[i] = rng();
            }
        }
    }
    initialized = true;
}

void send_message(vector<bool> M, vector<bool> Cvect)
{
    init();
    bitset<31> C;
    for (int i = 0; i < 31; i++)
    {
        C[i] = Cvect[i];
    }
    globC = C;
    deque<bool> X = prepareBits(M, C);
    int col = C.to_ullong() % 16;
    vector<bitset<31>> V(Q);

    int c1 = -1;
    int c = 0;
    for (int j = 0; j < 31; j++)
    {
        if (!C[j])
        {
            if (c == col)
            {
                c1 = j;
            }
            c++;
        }
    }
    for (int i = 0; i < Q; i++)
    {
        int c = 0;
        for (int j = 0; j < 31; j++)
        {
            if (j == c1 && i < 27)
            {
                c1 = j;
                V[i][j] = C[i + 4];
            }
            else if (!C[j])
            {
                V[i][j] = X.front();
                X.pop_front();
            }
            if (!C[i])
            {
                c++;
            }
        }
    }
    for (bitset<31> v : V)
    {
        send(v, C);
    }
}

std::vector<bool> receive_message(vector<vector<bool>> Rvect)
{
    init();
    vector<bitset<31>> R(Rvect.size());
    for (int i = 0; i < int(Rvect.size()); i++)
    {
        bitset<31> b;
        for (int j = 0; j < 31; j++)
        {
            b[j] = Rvect[i][j];
        }
        R[i] = b;
    }
    for (int i = 0; i < int(R.size()); i++)
    {
        R[i] = R[i] ^ masks[i];
    }
    if (R.size() != Q)
    {
        assert(false);
    }
    for (int col = 0; col < 16; col++)
    {
        for (int c1 = 0; c1 < 31; c1++)
        {
            bitset<31> C(col);
            for (int i = 0; i < 27; i++)
            {
                C[4 + i] = R[i][c1];
            }
            if (C.count() != 15)
            {
                continue;
            }
            if (C[c1])
            {
                continue;
            }
            int pos = 0;
            for (int i = 0; i < c1; i++)
            {
                if (!C[i])
                {
                    pos++;
                }
            }
            if (pos != col)
            {
                continue;
            }
            deque<bool> X;
            for (int i = 0; i < Q; i++)
            {
                int c = 0;
                for (int j = 0; j < 31; j++)
                {
                    if (j == c1 && i < 27)
                    {
                    }
                    else if (!C[j])
                    {
                        X.push_back(R[i][j]);
                    }
                    if (!C[i])
                    {
                        c++;
                    }
                }
            }
            mt19937_64 rng(C.to_ullong());
            bool ok = true;
            for (int i = 0; i < 16 * Q - 27 - 1025; i++)
            {
                bool v = rng() % 2 == 1;
                bool w = X.front();
                X.pop_front();
                if (v != w)
                {
                    ok = false;
                }
            }
            if (!ok)
            {
                continue;
            }
            int offset = 0;
            while (offset < int(X.size()) && X[offset])
            {
                offset++;
            }
            vector<bool> answer;
            for (int i = offset + 1; i < int(X.size()); i++)
            {
                answer.push_back(X[i]);
            }
            while (answer.size() < 1025)
            {
                answer.push_back(0);
            }
            while ((1024 - int(answer.size())) != offset && answer.size() > 0)
            {
                answer.pop_back();
            }
            return answer;
        }
    }
    assert(false);
    return {};
}

// vector<vector<bool>> sent;

// int main()
// {
//     mt19937_64 rng(5);
//     int maxQ = 0;
//     double avg = 0;
//     for (int i = 0; i < tests; i++)
//     {
//         vector<bool> msg(1024);
//         for (int i = 0; i < int(msg.size()); i++)
//         {
//             msg[i] = rng() % 2;
//         }
//         vector<bool> Cvect{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
//                            1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1};
//         shuffle(Cvect.begin(), Cvect.end(), rng);
//         send_message(msg,
//                      Cvect);
//         vector<bool> received = receive_message(sent);
//         maxQ = max(maxQ, int(sent.size()));
//         avg += sent.size();
//         if (msg != received)
//         {
//             cout << "maxQ: " << maxQ << " i: " << i << endl;
//             cout << "mismatch!" << endl;
//             for (int i : msg)
//             {
//                 cout << i;
//             }
//             cout << endl;
//             for (int i : received)
//             {
//                 cout << i;
//             }
//             cout << endl;
//             exit(0);
//         }
//         else
//         {
//         }
//         sent = {};
//     }
//     cout << maxQ << " " << avg / tests << endl;
// }

// vector<bool> send_packet(std::vector<bool> A)
// {
//     sent.push_back(A);
//     return A;
// }

• Subtask 0: 0 / 0
• Subtask 1: 9.5 / 10
• Subtask 2: 85.5 / 90