Submission #766880

#	Time	Username	Problem	Language	Result	Execution time	Memory
766880		jakobrs	Combo (IOI18_combo)	C++17	100 / 100	27 ms	500 KiB

combo

#include <iostream>
#include <random>
#include <string>

std::string guess_sequence(int N);

int press(std::string p);

using i64 = int64_t;

std::string guess_sequence(int n) {
    std::mt19937 rng(102435324);

    char cha = 'A';
    char chb = 'B';
    char chx = 'X';
    char chy = 'Y';
    
    if (press("AB") > 0) {
        if (press("A") > 0) {
            std::swap(cha, cha);
        } else {
            std::swap(cha, chb);
        }
    } else {
        if (press("X") > 0) {
            std::swap(cha, chx);
        } else {
            std::swap(cha, chy);
        }
    }

    std::string guess = { cha };
    std::string seq;

    for (i64 i = 1; i < n; i++) {
        if (i == n - 1) {
            if (press(guess + chb) > guess.size()) {
                guess += chb;
            } else if (press(guess + chx) > guess.size()) {
                guess += chx;
            } else {
                guess += chy;
            }
        } else {
            seq.clear();

            seq.append(guess);
            seq.push_back(chb);
            
            seq.append(guess);
            seq.push_back(chx);
            seq.push_back(chb);
        
            seq.append(guess);
            seq.push_back(chx);
            seq.push_back(chx);
        
            seq.append(guess);
            seq.push_back(chx);
            seq.push_back(chy);

            i64 result = press(seq);

            if (result == guess.size()) {
                guess += chy;
            } else if (result == guess.size() + 1) {
                guess += chb;
            } else {
                guess += chx;
            }
        }
    }

    // std::cout << guess << '\n';

    return guess;
}

Compilation message (stderr)

combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:38:36: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   38 |             if (press(guess + chb) > guess.size()) {
      |                 ~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~
combo.cpp:40:43: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   40 |             } else if (press(guess + chx) > guess.size()) {
      |                        ~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~
combo.cpp:65:24: warning: comparison of integer expressions of different signedness: 'i64' {aka 'long int'} and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   65 |             if (result == guess.size()) {
      |                 ~~~~~~~^~~~~~~~~~~~~~~
combo.cpp:67:31: warning: comparison of integer expressions of different signedness: 'i64' {aka 'long int'} and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   67 |             } else if (result == guess.size() + 1) {
      |                        ~~~~~~~^~~~~~~~~~~~~~~~~~~

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