Submission #291645

#	Time	Username	Problem	Language	Result	Execution time	Memory
291645		SamAnd	Combo (IOI18_combo)	C++17	100 / 100	93 ms	640 KiB

combo

#include "combo.h"
#include <bits/stdc++.h>
using namespace std;
#define m_p make_pair
#define fi first
#define se second
#define all(x) (x).begin(),(x).end()
#define sz(x) ((int)(x).size())
typedef long long ll;
const int N = 2003;
char u[4] = {'X', 'Y', 'A', 'B'};

std::string guess_sequence(int n)
{
    string s;
    for (int i = 0; i < n * 2; ++i)
        s += u[0];
    for (int i = 0; i < n * 2; ++i)
        s += u[1];
    if (press(s))
    {
        s.clear();
        for (int i = 0; i < n * 4; ++i)
            s += u[1];
        if (press(s))
            swap(u[1], u[0]);
    }
    else
    {
        s.clear();
        for (int i = 0; i < n * 4; ++i)
            s += u[2];
        if (press(s))
            swap(u[2], u[0]);
        else
            swap(u[3], u[0]);
    }

    string ans;
    ans += u[0];
    while (sz(ans) != n)
    {
        if (n - sz(ans) >= 2)
        {
            string s;
            s += ans;
            s += u[2];
            while (sz(s) % n != 0)
                s += u[0];
            for (int i = 1; i <= 3; ++i)
            {
                s += ans;
                s += u[1];
                s += u[i];
                while (sz(s) % n != 0)
                    s += u[0];
            }

            int x = press(s);
            if (x == sz(ans))
                ans += u[3];
            else if (x == sz(ans) + 1)
                ans += u[2];
            else
                ans += u[1];
        }
        else
        {
            for (int i = 1; i < 3; ++i)
            {
                string s;
                for (int j = 0; j < 4; ++j)
                {
                    s += ans;
                    s += u[i];
                }
                if (press(s) == n)
                {
                    ans += u[i];
                    break;
                }
            }
            if (sz(ans) != n)
                ans += u[3];
        }
    }
    return ans;
}

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