Submission #1211286

#	Time	Username	Problem	Language	Result	Execution time	Memory
1211286		sula2	Message (IOI24_message)	C++20	30.33 / 100	537 ms	860 KiB

message

#include "message.h"
#include <iostream>
#define all(a) a.begin(), a.end()
#define popcount(x) __builtin_popcountll(x)
using namespace std;

void send_message(vector<bool> message, vector<bool> C) {
    for (int i = 0; i < 30; i++) {
        send_packet(vector<bool>(31, C[i]));
    }
    vector<int> pos;
    for (int i = 0; i < 31; i++) if (C[i] == 0)
            pos.push_back(i);
    for (int i = 0; i < message.size(); i += 16) {
        vector<bool> packet(31);
        int j = i;
        for (int p : pos) if (j < message.size()) {
                packet[p] = message[j++];
            }
        send_packet(packet);
    }
    vector<bool> packet(31);
    for (int i = 0; i < 4; i++) {
        packet[pos[i]] = (message.size() % 16) >> i & 1;
    }
    send_packet(packet);
}

vector<bool> receive_message(vector<vector<bool>> packets) {
    vector<int> pos;
    for (int i = 0; i < 30; i++) {
        int cnt[2] = {};
        for (auto b : packets[i]) {
            cnt[b]++;
        }
        if (cnt[0] > cnt[1]) {
            pos.push_back(i);
        }
    }
    if (pos.size() < 16)
        pos.push_back(30);
    vector<bool> message;
    for (int i = 30; i < packets.size() - 2; i++) {
        for (int j : pos) {
            message.push_back(packets[i][j]);
        }
    }
    int to_read = 0;
    for (int i = 0; i < 4; i++) {
        to_read |= packets.back()[pos[i]] << i;
    }
    if (to_read == 0) to_read = 16;
    for (int i = 0; i < to_read; i++) {
        message.push_back(packets[packets.size() - 2][pos[i]]);
    }
    return message;
}

• Subtask 0: 0 / 0
• Subtask 1: 10 / 10
• Subtask 2: 20.3342 / 90