Submission #896130

#	Time	Username	Problem	Language	Result	Execution time	Memory
896130		wood	Combo (IOI18_combo)	C++17	100 / 100	13 ms	1900 KiB

combo

#include <bits/stdc++.h>  
using namespace std;
 
typedef long long ll;
typedef pair<int,int> p32;
typedef pair<ll,ll> p64;
#define pb push_back
#define eb emplace_back
#define fi first
#define se second
#define fast_cin() ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL)
int press(string p);

string guess_sequence(int n){
    string p = "";
    char start;
    if(press("AB")){
        if(press("A"))
        start = 'A';
        else start = 'B';
    } 
    else{
        if(press("X"))
        start = 'X';
        else start = 'Y';
    }
    p+=start;
    if(n>1){
        vector<char> ch = {'A','B','X','Y'};
        ch.erase(lower_bound(ch.begin(),ch.end(),start));
        for (int i = 0; i < n-2; i++)
        {
            int guess = press(p+ch[0]+ch[0]+p+ch[0]+ch[1]+p+ch[0]+ch[2]+p+ch[1]);
            if(guess==p.size()+2) p+=ch[0];
            else if(guess==p.size()+1) p+=ch[1];
            else p+=ch[2];
        }
        if(press(p+ch[0])==n) return p+ch[0];
        else if(press(p+ch[1])==n) return p+ch[1];
        else return p+ch[2];
    }
    else return p;
}

Compilation message (stderr)

combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:34:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   34 |             if(guess==p.size()+2) p+=ch[0];
      |                ~~~~~^~~~~~~~~~~~
combo.cpp:35:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   35 |             else if(guess==p.size()+1) p+=ch[1];
      |                     ~~~~~^~~~~~~~~~~~

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