Submission #826968

#	Time	Username	Problem	Language	Result	Execution time	Memory
826968		wortelworm	Combo (IOI18_combo)	C++17	100 / 100	27 ms	564 KiB

combo

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

std::string guess_sequence(int N) {
    char first;
    int coins = press("AB");
    if (coins > 0) {
        coins = press("A");
        if (coins > 0) {
            first = 'A';
        } else {
            first = 'B';
        }
    } else {
        coins = press("X");
        if (coins > 0) {
            first = 'X';
        } else {
            first = 'Y';
        }
    }

    string result = "";
    result += first;

    string options;
    for (char c : "ABXY") {
        if (c != first) {
            options += c;
        }
    }

    for (int i = 1; i < N; i++) {

        if (4*i + 7 <= 4*N) {
            coins = press(result + options[0]
                        + result + options[1] + options[0]
                        + result + options[1] + options[1]
                        + result + options[1] + options[2]);
            
            if (coins == result.size() + 1) {
                result += options[0];
            } else if (coins == result.size() + 2) {
                result += options[1];
            } else {
                result += options[2];
            }
        } else {
            for (int j = 0; j < 2; j++) {
                coins = press(result + options[j]);
                if (coins > result.size()) {
                    // this is correct
                    result += options[j];
                }
            }
            if (result.size() == i) {
                result += options[2];
            }
        }
    }

    return result;
}

Compilation message (stderr)

combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:43:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   43 |             if (coins == result.size() + 1) {
      |                 ~~~~~~^~~~~~~~~~~~~~~~~~~~
combo.cpp:45:30: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   45 |             } else if (coins == result.size() + 2) {
      |                        ~~~~~~^~~~~~~~~~~~~~~~~~~~
combo.cpp:53:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   53 |                 if (coins > result.size()) {
      |                     ~~~~~~^~~~~~~~~~~~~~~
combo.cpp:58:31: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   58 |             if (result.size() == i) {
      |                 ~~~~~~~~~~~~~~^~~~

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