Submission #701039

#	Time	Username	Problem	Language	Result	Execution time	Memory
701039		BobCompetitiveProgramming	Combo (IOI18_combo)	C++14	30 / 100	46 ms	472 KiB

combo

#include <bits/stdc++.h>
using namespace std; using ll=long long;


int press(std::string p);

string getRandom(string start, string no, int sz){
    while(start.size() < sz){
        int r = rand() % 4 + 1;
        if(r==1 && "A" != no) start += "A";
        if(r==2 && "B" != no) start += "B";
        if(r==3 && "X" != no) start += "X";
        if(r==4 && "Y" != no) start += "Y";
    }
    return start; 
}

string guess_sequence(int N){
    string S = "", first;
    if(press("AB")) {
        if(press("A")) first="A", S="A";
        else first="B", S="B";
    } else {
        if(press("X")) first="X", S="X";
        else first="Y", S="Y";
    }
        
    while(true){
        int curr_size = S.size();
        if(curr_size == N) 
            return S; 
        
        if(first=="X"){
            if(press(S+"A"+S+"B")>curr_size){
                if(press(S+"A")>curr_size) S+="A";
                else S+="B";
            } else
                S+="Y"; 
        }
        if(first=="Y"){
            if(press(S+"A"+S+"B")>curr_size){
                if(press(S+"A")>curr_size) S+="A";
                else S+="B";
            } else
                S+="X"; 
        }
        if(first=="A"){
            if(press(S+"B"+S+"X")>curr_size){
                if(press(S+"B")>curr_size) S+="B";
                else S+="X";
            } else
                S+="Y"; 
        }
        if(first=="B"){
            if(press(S+"A"+S+"X")>curr_size){
                if(press(S+"A")>curr_size) S+="A";
                else S+="X";
            } else
                S+="Y"; 
        }
    }   
}

Compilation message (stderr)

combo.cpp: In function 'std::string getRandom(std::string, std::string, int)':
combo.cpp:8:24: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
    8 |     while(start.size() < sz){
      |           ~~~~~~~~~~~~~^~~~

• Subtask 1: 5 / 5
• Subtask 2: 25 / 95