Submission #995293

#	Time	Username	Problem	Language	Result	Execution time	Memory
995293		biank	Data Transfer (IOI19_transfer)	C++14	100 / 100	220 ms	2764 KiB

transfer

#include "transfer.h"
 
using namespace std;
 
#define sz(x) int(x.size())
#define all(x) begin(x), end(x)
 
vector<int> parity(vector<int> source) {
    int log = sz(source) == 63 ? 6 : 8;
    vector<int> par(log, 0);
    for (int i = 0; i < sz(source); i++) {
        for (int j = 0; j < log; j++) {
            if ((i + 1) >> j & 1) par[j] ^= source[i];
        }
    }
    return par;
}
 
vector<int> get_attachment(vector<int> source) {
    vector<int> par = parity(source);
    int x = 0;
    for (int i = 0; i < sz(par); i++) {
        x ^= par[i];
    }
    par.push_back(x);
    return par;
}
 
vector<int> retrieve(vector<int> data) {
    int cut = sz(data) == 70 ? 63 : 255;
    vector<int> source(begin(data), begin(data) + cut);
    vector<int> code(begin(data) + cut, end(data));
    vector<int> par = parity(source);
    int x = 0;
    int p = 0;
    for (int i = 0; i < sz(code) - 1; i++) {
        if (code[i] != par[i]) x ^= 1 << i;
        p ^= code[i];
    }
    if (code.back() != p) return source;
    if (x != 0) source[x - 1] ^= 1;
    return source;
}

• Subtask 1: 60 / 60
• Subtask 2: 40 / 40