Submission #683958

#	Time	Username	Problem	Language	Result	Execution time	Memory
683958		Juan	Combo (IOI18_combo)	C++17	100 / 100	31 ms	588 KiB

combo

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


string guess_sequence(int N){
	string ans = "";
	char A, B, C, D;
	set<int> st;
	st.insert('A'), st.insert('B'), st.insert('X'), st.insert('Y');

	if(press("AB")){
		if(press("A")) A = 'A';
		else A = 'B';
	}
	else{
		if(press("X")) A = 'X';
		else A = 'Y';
	}
	ans+=A;
	if(N==1) return ans;
	st.erase(A);
	auto it = st.begin();
	B = *it, it++, C = *it, it++, D = *it;

	for(int i = 1; i < N-1; i++){
		string aux="";
		aux+=ans, aux+=B;
		aux+=ans, aux+=C, aux+=B;
		aux+=ans, aux+=C, aux+=C;
		aux+=ans, aux+=C, aux+=D;
		int prs = press(aux) - i;
		if(prs==0)
			ans+=D;
		else if(prs==1)
			ans+=B;
		else if(prs==2)
			ans+=C;
	}

	string aux = "";
	aux+=ans, aux+=B;
	if(press(aux)==N) ans+=B;
	else{
		aux.pop_back();
		aux+=C;
		if(press(aux)==N) ans+=C;
		else ans+=D;
	}

	return ans;
}

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