Submission #411403

#	Time	Username	Problem	Language	Result	Execution time	Memory
411403		usachevd0	Combo (IOI18_combo)	C++17	100 / 100	42 ms	576 KiB

combo

#include <bits/stdc++.h>
#ifndef LOCAL
    #include "combo.h"
#endif

using namespace std;

#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define all(a) (a).begin(), (a).end()
#define Time (clock() * 1.0 / CLOCKS_PER_SEC)
using ll = long long;
using ull = unsigned long long;
using pii = pair<int, int>;
using pil = pair<int, ll>;
using pli = pair<ll, int>;
using pll = pair<ll, ll>;
using ld = long double;
template<typename T1, typename T2> bool chkmin(T1& x, T2 y) {
    return y < x ? (x = y, true) : false;
}
template<typename T1, typename T2> bool chkmax(T1& x, T2 y) {
    return y > x ? (x = y, true) : false;
}
void debug_out() {
    cerr << endl;
}
template<typename T1, typename... T2> void debug_out(T1 A, T2... B) {
    cerr << ' ' << A;
    debug_out(B...);
}
template<typename T> void mdebug_out(T* a, int n) {
    for (int i = 0; i < n; ++i)
        cerr << a[i] << ' ';
    cerr << endl;
}
#ifdef LOCAL
    #define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
    #define mdebug(a, n) cerr << #a << ": ", mdebug_out(a, n)
#else
    #define debug(...) 1337
    #define mdebug(a, n) 1337
#endif
template<typename T> ostream& operator << (ostream& stream, const vector<T>& v) {
    for (auto& x : v)
        stream << x << ' ';
    return stream;
}
template<typename T1, typename T2> ostream& operator << (ostream& stream, const pair<T1, T2>& p) {
    return stream << p.first << ' ' << p.second;
}

#ifdef LOCAL
    mt19937 rng(228);
    int n;
    string s;
    int press(string p) {
        int mx = 0;
        for (int i = 0; i < p.size(); ++i) {
            int lcp = 0;
            while (lcp < n && i + lcp < p.size() && s[lcp] == p[i + lcp])
                ++lcp;
            chkmax(mx, lcp);
        }
        return mx;
    }
#endif

const string ch[4] = {"A", "B", "X", "Y"};

// int Press(vector<int> v) {
//     string s(v.size());
//     for (int i = 0; i < v.size(); ++i)
//         s[i] = ch[v[i]];
//     returu press(s);
// }

string guess_sequence(int n) {
    if (n == 1) {
        int z = 0;
        while (z < 3 && press(ch[z]) == 0)
            ++z;
        return ch[z];
    }
    
    mt19937 rng(time(0));
    // vector<int> ord_z = {0, 1, 2, 3};
    // shuffle(all(ord_z), rng);
    // int zi = 0;
    // while (zi < 3 && press(ch[ord_z[zi]] ) == 0)
    //     ++zi;
    // int z = ord_z[zi];
    
    int z;
    if (press(ch[0] + ch[1])) {
        if (press(ch[0])) {
            z = 0;
        } else {
            z = 1;
        }
    } else {
        if (press(ch[2])) {
            z = 2;
        } else {
            z = 3;
        }
    }
    
    vector<string> rem;
    for (int i = 0; i < 4; ++i)
        if (i != z)
            rem.push_back(ch[i]);
    
    string cur = ch[z];
    for (int i = 1; i + 1 < n; ++i) {
        string q = cur + rem[0] + rem[0] + cur + rem[0] + rem[1] + cur + rem[0] + rem[2] + cur + rem[1];
        int res = press(q);
        if (res == i) {
            cur += rem[2];
        } else if (res == i + 1) {
            cur += rem[1];
        } else {
            cur += rem[0];
        }
    }
    
    vector<int> ord_l = {0, 1, 2};
    shuffle(all(ord_l), rng);
    int li = 0;
    while (li < 2 && press(cur + rem[ord_l[li]]) < n)
        ++li;
    int l = ord_l[li];
    cur += rem[l];
    return cur;
}


#ifdef LOCAL
int32_t main() {
#ifdef LOCAL
    freopen("in", "r", stdin);
#endif
    ios::sync_with_stdio(0);
    cin.tie(0);

    for (int test = 1; ; ++test) {
        n = 10;
        int z = rng() % 4;
        s = ch[z];
        vector<string> rem;
        for (int i = 0; i < 4; ++i)
            if (i != z)
                rem.push_back(ch[i]);
        for (int i = 1; i < n; ++i)
            s += rem[rng() % 3];
        if (guess_sequence(n) != s) {
            debug(s);
            exit(0);
        }
        if (test % 10000 == 0) debug(test);
    }/**/
    
    cin >> s;
    n = s.size();
    cout << guess_sequence(n) << '\n';

    return 0;
}
#endif

• Subtask 1: 5 / 5
• Subtask 2: 95 / 95