Submission #623464

#	Time	Username	Problem	Language	Result	Execution time	Memory
623464		lcj	Data Transfer (IOI19_transfer)	C++17	40 / 100	274 ms	2588 KiB

transfer

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;

#include "transfer.h"

std::vector<int> get_attachment(vector<int> source) {
    int n = source.size();
    int k;
    if (n == 63) {
        k = 6;
    }
    else {
        k = 8;
    }
    vector<int> at(k+1, 0);
    for (int i = 1; i <= n; i++)
    {
        for (int j = 0; j < k; j++)
        {
            if (i & (1 << j)) {
                at[j] ^= source[i-1];
            }
        }
    }
    for (int i = 0; i < k; i++)
    {
        at[k] ^= at[i];
    }
	return at;
}

std::vector<int> retrieve(std::vector<int> data) {
    int n, k;
    if (data.size() == 70) {
        n = 63;
        k = 6;
    }
    else  {
        n = 255;
        k = 8;
    }
    int cxor = 0;
    for (int i = n; i <= data.size(); i++)
    {
        cxor ^= data[i];
    }
    if (cxor) {
        return vector<int>(data.begin(), data.begin()+n);
    }
    vector<int> at(k, 0);
    for (int i = 1; i <= n; i++)
    {
        for (int j = 0; j < k; j++)
        {
            if (i & (1 << j)) {
                at[j] ^= data[i-1];
            }
        }
    }
    int num = 0;
    for (int j = 0; j < k; j++)
    {
        if (data[n+j] != at[j]) {
            num |= (1 << j);
        }
    }
    if (num != 0) data[num-1] ^= 1;
	return std::vector<int>(data.begin(), data.begin()+n);
}

Compilation message (stderr)

transfer.cpp: In function 'std::vector<int> retrieve(std::vector<int>)':
transfer.cpp:48:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   48 |     for (int i = n; i <= data.size(); i++)
      |                     ~~^~~~~~~~~~~~~~

• Subtask 1: 0 / 60
• Subtask 2: 40 / 40