Submission #675772

#	Time	Username	Problem	Language	Result	Execution time	Memory
675772		GGOSHAB	Combo (IOI18_combo)	C++14	5 / 100	12 ms	324 KiB

combo

#include <iostream>
#include <vector>
#include "combo.h"

#define PI 3.14159265359

using namespace std;

typedef long long ll;
typedef unsigned long long ull;

typedef vector<int> bigInt;

const ull INF = -1;

string guess_sequence(int n) {
    string ans;
    ans.reserve(n);
    if (press("AB")) {
        if (press("A"))
            ans.push_back('A');
        else
            ans.push_back('B');
    }
    else {
        if (press("X"))
            ans.push_back('X');
        else
            ans.push_back('Y');
    }

    char ex = ans[0];
    string t, letters = "ABXY", tl;

    for (char c : letters)
        if (c != ex)
            tl.push_back(c);


    t.reserve(4 * n); // TODO: Double guess
    bool x = 0;
    for (int i = 2; i <= n; ++i) {
        t = "";
        t.reserve(4 * n);
        for (int i = 0; i < 3; ++i) {
                t += ans;
                t.push_back(tl[i]);
                t.push_back(tl[0]);
        }
        if (!x) {
            int p = press(t.substr(0, (i << 1) + 2));
            x = p > i;
            if (p >= i) {
                p = press(t.substr(0, i + 1));
                if (p >= i) {
                    ans.push_back(tl[0]);
                    if (x) {
                        ans.push_back(tl[0]);
                        i++;
                    }
                }
                else {
                    ans.push_back(tl[1]);
                    if (x) {
                        ans.push_back(tl[0]);
                        i++;
                    }
                }
            }
            else {
                ans.push_back(tl[2]);
            }
        }
        else
        {
            x = 0;
            int p = press(t.substr(i + 1, i + 1));
            if (p >= i) {
                ans.push_back(tl[1]);
                if (p > i) {
                    x = 1;
                    ans.push_back(tl[0]);
                }
                else
                    ans.push_back(tl[2]);
            }
        }
    }

    return ans;
}

• Subtask 1: 5 / 5
• Subtask 2: 0 / 95