Submission #237469

#	Time	Username	Problem	Language	Result	Execution time	Memory
237469		A02	Combo (IOI18_combo)	C++14	100 / 100	42 ms	612 KiB

combo

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

using namespace std;

string guess_sequence(int N) {
    string p = "AB";
    int coins = press(p);

    string S = "";
    char first = 'A';

    if (coins > 0){
        coins = press("A");
        if (coins > 0){
            S = "A";
            first = 'A';
        } else {
            first = 'B';
            S = "B";
        }
    } else {

        coins = press("X");
        if (coins > 0){
            S = "X";
            first = 'X';
        } else {
            first = 'Y';
            S = "Y";
        }
    }


    vector<char> not_first;
    vector<char> possible;
    possible.push_back('A');
    possible.push_back('B');
    possible.push_back('X');
    possible.push_back('Y');
    for (int i = 0; i < 4; i++){
        if (possible[i] != first){
            not_first.push_back(possible[i]);
        }
    }

    while (S.size() < N){
        //cout << S << ' ' << N << endl;
        int t = S.size();
        if (S.size() == N - 1){
            coins = press(S + not_first[0] + S + not_first[1]);
            if (coins == t){
                S += not_first[2];
                break;
            }
            coins = press(S + not_first[0]);
            if (coins == t + 1){
                S += not_first[0];
                break;
            }
            S += not_first[1];
            break;
        }

        string to_test = S + not_first[0] + not_first[0] + S + not_first[0] + not_first[1] + S + not_first[0] + not_first[2] + S + not_first[1];
        coins = press(to_test);

        if (coins == t + 2){
            S = S + not_first[0];

        }
        if (coins == t + 1){
            S = S + not_first[1];
        }

        if (coins == t){
            S = S + not_first[2];
        }

    }
    //cout << S << endl;
    return S;
}

Compilation message (stderr)

combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:48:21: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   48 |     while (S.size() < N){
      |            ~~~~~~~~~^~~
combo.cpp:51:22: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   51 |         if (S.size() == N - 1){
      |             ~~~~~~~~~^~~~~~~~

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