Submission #529004

#	Time	Username	Problem	Language	Result	Execution time	Memory
529004		tabr	Data Transfer (IOI19_transfer)	C++17	100 / 100	76 ms	2480 KiB

transfer

#ifndef tabr
#include "transfer.h"
#endif
#include <bits/stdc++.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++) {
        if (a[i]) {
            c ^= i + 1;
        }
    }
    for (int i = 0; i < (1 << (q + 1)); i++) {
        if (__builtin_parity(i) == 0) {
            if (c == 0) {
                vector<int> b;
                for (int j = 0; j < q + 1; j++) {
                    if (i & (1 << j)) {
                        b.emplace_back(1);
                    } else {
                        b.emplace_back(0);
                    }
                }
                return b;
            }
            c--;
        }
    }
    return vector<int>();
}
 
vector<int> retrieve(vector<int> a) {
    int n = 1;
    int q = 1;
    while (n + q + 1 < (int) a.size()) {
        n *= 2;
        n++;
        q++;
    }
    int c = 0;
    for (int i = n; i < n + q + 1; i++) {
        c ^= a[i] << (i - n);
    }
    a.resize(n);
    if (__builtin_parity(c) == 1) {
        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++) {
        if (a[i]) {
            b ^= i + 1;
        }
    }
    if (b > 0) {
        a[b - 1] ^= 1;
    }
    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 = 7;
    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

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