Submission #524260

#	Time	Username	Problem	Language	Result	Execution time	Memory
524260		tabr	Unscrambling a Messy Bug (IOI16_messy)	C++17	100 / 100	2 ms	460 KiB

messy

#include <bits/stdc++.h>
using namespace std;
#ifdef tabr
#include "library/debug.cpp"
#else
#define debug(...)
#endif

#ifdef tabr
function<void(string)> add_element;
function<void()> compile_set;
function<bool(string)> check_element;
#else
#include "messy.h"
#endif

vector<int> restore_permutation(int n, int, int) {
    int k = __builtin_ctz(n);
    for (int i = 0; i < k; i++) {
        string s(n, '0');
        s[i] = '1';
        add_element(s);
    }
    for (int i = 0; i < k - 1; i++) {
        string s(n, '0');
        s[i] = s[i + 1] = '1';
        add_element(s);
    }
    vector<vector<int>> cnt(k, vector<int>(n));
    for (int i = k; i < n; i++) {
        for (int j = 0; j < k; j++) {
            if (i & (1 << j)) {
                string s(n, '0');
                s[i] = s[j] = '1';
                add_element(s);
            }
        }
        int pp = 0;
        for (int j = k - 1; j >= 0; j--) {
            pp |= i & (1 << j);
            cnt[j][pp]++;
        }
    }
    {
        string s(n, '1');
        s[0] = '0';
        add_element(s);
    }
    compile_set();
    vector<int> p(n, -1);
    set<int> st;
    for (int i = 0; i < n; i++) {
        string s(n, '0');
        s[i] = '1';
        if (check_element(s)) {
            st.emplace(i);
        }
    }
    vector<int> q(k);
    for (int i : st) {
        string s(n, '1');
        s[i] = '0';
        if (check_element(s)) {
            q[0] = i;
            st.erase(i);
            break;
        }
    }
    for (int i = 1; i < k - 1; i++) {
        for (int j : st) {
            string s(n, '0');
            s[q[i - 1]] = s[j] = '1';
            if (check_element(s)) {
                q[i] = j;
                st.erase(j);
                break;
            }
        }
    }
    q[k - 1] = *st.begin();
    for (int i = 0; i < k; i++) {
        p[q[i]] = i;
    }
    for (int j = k - 1; j >= 0; j--) {
        for (int i = 0; i < n; i++) {
            if (p[i] >= 0) {
                continue;
            }
            int pp = ~p[i];
            if (cnt[j][pp] == 0) {
                p[i] ^= 1 << j;
                cnt[j][~p[i]]--;
                continue;
            }
            pp ^= 1 << j;
            if (cnt[j][pp] == 0) {
                cnt[j][~p[i]]--;
                continue;
            }
            string s(n, '0');
            s[i] = s[q[j]] = '1';
            if (check_element(s)) {
                p[i] ^= 1 << j;
            }
            cnt[j][~p[i]]--;
        }
    }
    for (int i = 0; i < n; i++) {
        p[i] = max(p[i], ~p[i]);
    }
    return p;
}

#ifdef tabr
int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n;
    cin >> n;
    mt19937 rng((unsigned int) chrono::steady_clock::now().time_since_epoch().count());
    vector<int> p(n);
    iota(p.begin(), p.end(), 0);
    shuffle(p.begin(), p.end(), rng);
    vector<string> t;
    int cnt0 = 0;
    int cnt1 = 0;
    add_element = [&](string x) {
        cnt0++;
        t.emplace_back(x);
    };
    compile_set = [&]() {
        for (string& x : t) {
            string y = x;
            for (int i = 0; i < n; i++) {
                x[p[i]] = y[i];
            }
        }
        sort(t.begin(), t.end());
    };
    check_element = [&](string x) {
        cnt1++;
        return binary_search(t.begin(), t.end(), x);
    };
    auto q = restore_permutation(n, 0, 0);
    for (int i = 0; i < n; i++) {
        assert(q[p[i]] == i);
    }
    debug(cnt0, cnt1);
    return 0;
}
#endif

• Subtask 1: 20 / 20
• Subtask 2: 18 / 18
• Subtask 3: 11 / 11
• Subtask 4: 21 / 21
• Subtask 5: 30 / 30