Submission #566348

#	Time	Username	Problem	Language	Result	Execution time	Memory
566348		elazarkoren	Combo (IOI18_combo)	C++17	100 / 100	32 ms	592 KiB

combo

#include <bits/stdc++.h>
#include "combo.h"
#define x first
#define y second
#define all(v) v.begin(), v.end()
#define chkmin(a, b) a = min(a, b)
#define chkmax(a, b) a = max(a, b)
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int, int> pii;
typedef vector<pii> vii;

mt19937 rng(time(0));

//char letters[] = {'A', 'B', 'X', 'Y'};
string buttons[] = {"A", "B", "X", "Y"};

string guess_sequence(int n) {
    string p = "";
    if (press("AB") >= 1) {
        if (press("A") >= 1) p.push_back('A');
        else p.push_back('B');
    } else {
        if (press("X") >= 1) p.push_back('X');
        else p.push_back('Y');
    }
    if (n == 1) return p;
    vector<string> letters;
    for (string s : buttons) {
        if (s[0] != p[0]) letters.push_back(s);
    }
    for (int i = 1; i < n - 1; i++) {
        shuffle(all(letters), rng);
        string curr = "";
        for (int j = 0; j < 3; j++) {
            curr += p + letters[0] + letters[j];
        }
        curr += p + letters[1];
        int coins = press(curr);
        if (coins == i + 1) {
            p += letters[1];
        } else if (coins == i) {
            p += letters[2];
        } else {
            p += letters[0];
        }
    }
    if (press(p + letters[0] + p + letters[1]) == n) {
        if (press(p + letters[0]) == n) p += letters[0];
        else p += letters[1];
    } else {
        p += letters[2];
    }
    return p;
}

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