Submission #1164138

#	Time	Username	Problem	Language	Result	Execution time	Memory
1164138		canhnam357	Combo (IOI18_combo)	C++20	100 / 100	8 ms	564 KiB

combo

#include <bits/stdc++.h>
#include "combo.h"
using namespace std;
// string S = "ABXYY";
// // z[i] = length of longest common prefix of s[0..N] and s[i..N]
// vector<int> zfunc(const string& s) {
//     int n = (int)s.length();
//     vector<int> z(n);
//     z[0] = n;
//     for (int i = 1, l = 0, r = 0; i < n; ++i) {
//         if (i <= r)
//             z[i] = min(r - i + 1, z[i - l]);
//         while (i + z[i] < n && s[z[i]] == s[i + z[i]])
//             ++z[i];
//         if (i + z[i] - 1 > r)
//             l = i, r = i + z[i] - 1;
//     }
//     return z;
// }
// int press(string p)
// {
//     string s = S + "#" + p;
//     vector<int> z = zfunc(s);
//     return *max_element(z.begin() + (int)(S.size()), z.end());
// }
auto seed = chrono::high_resolution_clock::now().time_since_epoch().count();
mt19937_64 mt(seed);
long long get_random(long long l, long long r, bool non_zero = 0)
{
    assert(l <= r);
    long long res;
    while (true)
    {
        res = mt() % (r - l + 1) + l;
        if (non_zero && !res) continue;
        break;
    }
    return res;
}
string guess_sequence(int N)
{
    int asked = 0;
    string chars = "ABXY";
    string t = "";
    if (press(chars.substr(0, 2)))
    {
        if (press(chars.substr(0, 1)))
        {
            t += chars[0];
            chars.erase(0, 1);
        }
        else
        {
            t += chars[1];
            chars.erase(1, 1);
        }
    }
    else
    {
        if (press(chars.substr(2, 1)))
        {
            t += chars[2];
            chars.erase(2, 1);
        }
        else
        {
            t += chars[3];
            chars.erase(3, 1);
        }
    }
    if (N == 1) return t;
    asked += 2;
    for (int i = 2; i < N; i++)
    {
        string a = t;
        a += chars[0];
        string b = t;
        b += chars[1];
        string s = a;
        for (char c : chars)
        {
            b += c;
            s += b;
            b.pop_back();
        }
        asked++;
        int k = press(s);
        if (k == i) t += chars[0];
        else if (k == i + 1) t += chars[1];
        else t += chars[2];
    }
    if (press(t + chars.substr(0, 1)) == N)
    {
        t += chars[0];
    }
    else if (press(t + chars.substr(1, 1)) == N)
    {
        t += chars[1];
    }
    else t += chars[2];
    //cout << "ASKED " << asked << '\n';
    return t;
}
// int main()
// {
//     cout << guess_sequence(S.size());
//     return 0;
// }

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