Submission #750546

#	Time	Username	Problem	Language	Result	Execution time	Memory
750546		xink	Combo (IOI18_combo)	C++14	100 / 100	34 ms	560 KiB

combo

#include "combo.h"
#include <iostream>
#include <vector>
#include <utility>
#include <sstream>
#include <climits>
#include <cstring>
#define ll long long
#define ld long double
using namespace std;
const ll mod = 1e9 + 7;
typedef vector<int> vi;
typedef pair<int, int> ii;
typedef vector<ii> vii;

void get_first_letter(string &str, string &letter)
{
    if (press("AB") > 0)
    {
        if (press("A") > 0)
        {
            str.push_back('A');
        }
        else
        {
            str.push_back('B');
            swap(letter[0], letter[1]);
        }
    }
    else
    {
        if (press("X") > 0)
        {
            str.push_back('X');
            swap(letter[0], letter[2]);
        }
        else
        {
            str.push_back('Y');
            swap(letter[0], letter[3]);
        }
    }
}

void get_last_letter(string &str, string &letter)
{
    if (press(str + letter[1]) == (int)str.size() + 1)
    {
        str.push_back(letter[1]);
    }
    else if (press(str + letter[2]) == (int)str.size() + 1)
    {
        str.push_back(letter[2]);
    }
    else
    {
        str.push_back(letter[3]);
    }
}

string guess_sequence(int n)
{
    string ans, letter = "ABXY";
    get_first_letter(ans, letter);
    for (int i = 1; i < n - 1; i++)
    {
        int coin = press(ans + letter[1] + ans + letter[2] + letter[1] + ans + letter[2] + letter[2] + ans + letter[2] + letter[3]);
        if (coin == i)
        {
            ans.push_back(letter[3]);
        }
        else if (coin == i + 1)
        {
            ans.push_back(letter[1]);
        }
        else
        {
            ans.push_back(letter[2]);
        }
    }
    if (ans.size() == n - 1)
        get_last_letter(ans, letter);
    return ans;
}

Compilation message (stderr)

combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:81:20: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   81 |     if (ans.size() == n - 1)
      |         ~~~~~~~~~~~^~~~~~~~

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