Submission #528955

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
528955	2022-02-21T20:34:30 Z	tabr	Data Transfer (IOI19_transfer)	C++17	Compilation error	0 ms	0 KB

transfer

#include "transfer.h"
using namespace std;
#ifdef tabr
#include "library/debug.cpp"
#else
#define debug(...)
#endif

vector<int> get_attachment(vector<int> a) {
    int n = (int) a.size();
    int q = __builtin_popcount(n);
    int c = 0;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < q; j++) {
            if ((i + 1) & (1 << j)) {
                c ^= a[i] << j;
            }
        }
    }
    for (int i = 0; i < (1 << (q + 1)); i++) {
        if (__builtin_parity(i) == 0) {
            if (c == 0) {
                for (int j = 0; j < q + 1; j++) {
                    if (i & (1 << j)) {
                        a.emplace_back(1);
                    } else {
                        a.emplace_back(0);
                    }
                }
                return a;
            }
            c--;
        }
    }
    assert(false);
    return vector<int>();
}

vector<int> retrieve(vector<int> a) {
    int n = 1;
    int q = 2;
    while (n + q != (int) a.size()) {
        n *= 2;
        n++;
        q++;
    }
    int c = 0;
    for (int i = n; i < n + q; i++) {
        c ^= a[i] << (i - n);
    }
    if (__builtin_parity(c) == 1) {
        a.resize(n);
        return a;
    }
    int b = 0;
    for (int i = 0; i < c; i++) {
        if (__builtin_parity(i) == 0) {
            b++;
        }
    }
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < q; j++) {
            if ((i + 1) & (1 << j)) {
                b ^= a[i] << j;
            }
        }
    }
    if (b > 0) {
        a[b - 1] ^= 1;
    }
    a.resize(n);
    return a;
}

mt19937 rng((unsigned int) chrono::steady_clock::now().time_since_epoch().count());

int rand_int(int a, int b) {  // [a, b]
    return uniform_int_distribution<int>(a, b)(rng);
}

#ifdef tabr
int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n = 63;
    int tt = 1000;
    while (tt--) {
        vector<int> a(n);
        for (int i = 0; i < n; i++) {
            a[i] = rand_int(0, 1);
        }
        auto b = get_attachment(a);
        int pos = rand_int(-1, (int) b.size() - 1);
        if (pos >= 0) {
            b[pos] ^= 1;
        }
        auto c = retrieve(b);
        if (a == c) {
            // cerr << "OK" << endl;
        } else {
            cerr << "NG" << endl;
            debug(pos);
            debug(a);
            debug(b);
            debug(c);
        }
    }
    return 0;
}
#endif

Compilation message

transfer.cpp: In function 'std::vector<int> get_attachment(std::vector<int>)':
transfer.cpp:35:5: error: 'assert' was not declared in this scope
   35 |     assert(false);
      |     ^~~~~~
transfer.cpp:2:1: note: 'assert' is defined in header '<cassert>'; did you forget to '#include <cassert>'?
    1 | #include "transfer.h"
  +++ |+#include <cassert>
    2 | using namespace std;
transfer.cpp: At global scope:
transfer.cpp:75:1: error: 'mt19937' does not name a type
   75 | mt19937 rng((unsigned int) chrono::steady_clock::now().time_since_epoch().count());
      | ^~~~~~~
transfer.cpp: In function 'int rand_int(int, int)':
transfer.cpp:78:12: error: 'uniform_int_distribution' was not declared in this scope
   78 |     return uniform_int_distribution<int>(a, b)(rng);
      |            ^~~~~~~~~~~~~~~~~~~~~~~~
transfer.cpp:78:37: error: expected primary-expression before 'int'
   78 |     return uniform_int_distribution<int>(a, b)(rng);
      |                                     ^~~
transfer.cpp:78:37: error: expected ';' before 'int'
   78 |     return uniform_int_distribution<int>(a, b)(rng);
      |                                     ^~~
      |                                     ;
transfer.cpp:78:40: error: expected unqualified-id before '>' token
   78 |     return uniform_int_distribution<int>(a, b)(rng);
      |                                        ^