Submission #1285904

#	Time	Username	Problem	Language	Result	Execution time	Memory
1285904		minhnguyent546	Data Transfer (IOI19_transfer)	C++20	Compilation error	0 ms	0 KiB

transfer

/**            
 * author      minhnguyent546
 * created_at  Fri, 2025-10-31 21:24:00
 **/           
#include <vector>
#include <cassert>
#include "transfer.h"


std::vector<int> get_attachment(std::vector<int> source) {
    int n = (int) source.size();
    assert (n == 63 || n == 255);
    int x = 0;
    for (int i = 0; i < n; ++i) {
        if (source[i] == 1) x ^= (i + 1);
    }
    // cerr << "x = " << x << '\n';
    int sz;
    if (n == 63) {
        sz = 6;
    } else {
        sz = 8;
    }
    std::vector<int> b(sz + 1);
    int cur = x;
    int one = 0;
    for (int i = 0; i < sz; ++i) {
        if ((cur >> i) & 1) {
            ++one;
            b[i] = 1;
        }
    }
    b[sz] = (one & 1 ? 1 : 0);
    return b;
}

std::vector<int> retrieve(std::vector<int> data) {
    int sz = (int) data.size();
    int k, n;
    assert(sz == 70 || sz == 264);
    if (sz == 70) {
        n = 63;
        k = 6;
    } else {
        n = 255;
        k = 8;
    }
    int one = 0;
    for (int i = n; i < sz; ++i) {
        one += data[i];
    }
    if (one % 2 == 0) {
        // corrupted in N bits
        int x = 0;
        for (int i = 0; i < k; ++i) {
            if (data[i + n] == 1) {
                x += (1 << i);
            }
        }
        for (int i = 0; i < n; ++i) {
            if (data[i] == 1) x ^= (i + 1);
        }
        // corrupted position is x;
        cerr << "x = " << x << '\n';
        assert (x >= 0 && x <= n);
        if (x > 0) {
            data[x - 1] ^= 1;
        }   
    } else {
        // corrupted in K bits;
    }
    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:64:9: error: 'cerr' was not declared in this scope
   64 |         cerr << "x = " << x << '\n';
      |         ^~~~
grader.cpp: In instantiation of 'void shuffle(std::vector<T>&) [with T = Scenario]':
grader.cpp:200:10:   required from here
grader.cpp:28:23: warning: 'void std::random_shuffle(_RAIter, _RAIter) [with _RAIter = __gnu_cxx::__normal_iterator<Scenario*, vector<Scenario> >]' is deprecated: use 'std::shuffle' instead [-Wdeprecated-declarations]
   28 |         random_shuffle(v.begin(), v.end());
      |         ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/13/algorithm:61,
                 from grader.cpp:8:
/usr/include/c++/13/bits/stl_algo.h:4581:5: note: declared here
 4581 |     random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last)
      |     ^~~~~~~~~~~~~~