Submission #1137858

#	Time	Username	Problem	Language	Result	Execution time	Memory
1137858		Shadow1	Combo (IOI18_combo)	C++20	100 / 100	7 ms	508 KiB

combo

#include "combo.h"
using namespace std;
#include <bits/stdc++.h>

using ll = long long;
using ld = long double;
using ull = unsigned long long;
using str = string; // yay python!

#define sz(x) ll(x.size())
#define all(x) x.begin(), x.end()
#define show(x) cerr << (#x) << " = " << (x) << '\n';
#define output_vector(v) for(auto &x : v){cout << x << ' ';}cout << '\n';

std::string guess_sequence(int N) {
    vector<char> butt = {'A', 'B', 'X', 'Y'};
    int x = press("AB");
    char first;
    if(x) {
        x = press("A");
        if(x) first = 'A';
        else first = 'B';
    } else {
        x = press("X");
        if(x) first = 'X';
        else first = 'Y';
    }
    str ans = "", s = "";
    ans += first;
    s += first;
    if(N == 1) {
        return s;
    }
    butt.erase(find(all(butt), first));
    for(int i=1; i<N-1; ++i) {
        char k = butt[0];
        str p = "";
        for(auto &v : butt) {
            p += s + k + v;
        }
        p += s + butt[1];
        x = press(p);
        if(x >= sz(s) + 2) {
            s += butt[0];
        } else if(x >= sz(s) + 1) {
            s += butt[1];
        } else {
            s += butt[2];
        }
    }
    x = press(s + butt[0]);
    if(x == N)
        s += butt[0];
    else {
        x = press(s + butt[1]);
        if(x == N)
            s += butt[1];
        else
            s += butt[2];
    }
    return s;
}

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