Submission #827132

#	Time	Username	Problem	Language	Result	Execution time	Memory
827132		HamletPetrosyan	Combo (IOI18_combo)	C++17	100 / 100	28 ms	604 KiB

combo

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

#define len(a) ((int)(a).size())

string guess_sequence(int N) {
	string p = "";
	int x;
	char ch[4] = {'A', 'B', 'X', 'Y'};
	
	x = press("AB");
	if(x == 2) p += "AB";
	else if(x){
		x = press("A");
		if(x) p += "A";
		else p += "B";
	}
	else{
		x = press("X");
		if(x) p += "X";
		else p += "Y";
	}

	if(N == len(p)) return p;

	vector<char> v;
	for(int i = 0; i < 4; i++){
		if(ch[i] == p[0]) continue;
		v.push_back(ch[i]);
	}

	for(int i = len(p) + 1; i < N; i++){
		x = press(p + v[0] + p + v[1] + v[0] + p + v[1] + v[1] + p + v[1] + v[2]);
		if(x == len(p) + 1) p += v[0];
		else if(x == len(p) + 2) p += v[1];
		else p += v[2];
	}
	x = press(p + v[0]);
	if(x == N) p += v[0];
	else{
		x = press(p + v[1]);
		if(x == N) p += v[1];
		else p += v[2];
	}
	return p;
}

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