Submission #760924

#	Time	Username	Problem	Language	Result	Execution time	Memory
760924		midi	Combo (IOI18_combo)	C++14	5 / 100	1 ms	256 KiB

combo

#include "combo.h"
#include <bits/stdc++.h>
using namespace std;
	
typedef long long ll;
typedef vector<ll> vcll;
typedef vector<int> vci;
typedef pair<ll, ll> prll;
typedef pair<int, int> prii;
	
#define f0r(i, a, n) for (i = a; i < n; i++)
#define f1r(i, a, n) for (i = a; i <= n; i++)
#define r0f(i, n, a) for (i = n; i > a; i--)
#define r1f(i, n, a) for (i = n; i >= a; i--)
	
#define pb push_back
	
char tar[] = {'A', 'B', 'X', 'Y', 'A', 'B', 'X'};
	
char A, B, C, D;

void init(char start)
{
	ll n = sizeof(tar);
	ll i;
	
	f0r(i, 0, n)
		if (tar[i] == start) break;
	
	A = tar[i++];
	B = tar[i++];
	C = tar[i++];
	D = tar[i++];
}

void paste(string &from, string &to)
{
	for (auto const &c : from)
		to.pb(c);
}

string guess_sequence(int N)
{
	ll n = N;
	string builder;
	ll res = press("AB");
	char start;
	
	if (res)
	{
		res = press("A");
		if (res) start = 'A';
		else start = 'B';
	}
	else
	{
		res = press("X");
		if (res) start = 'X';
		else start = 'Y';
	}
	
	init(start);
	builder.pb(A);

	// first char, done
	
	ll i = 0;
	string pusher, adder;

	f0r(i, 1, n-1)
	{
		paste(builder, pusher);
		adder.pb(B);
		paste(adder, pusher);
		adder.clear();

		paste(builder, pusher);
		adder.pb(C); adder.pb(B);
		paste(adder, pusher);
		adder.clear();

		paste(builder, pusher);
		adder.pb(C); adder.pb(C);
		paste(adder, pusher);
		adder.clear();
	
		paste(builder, pusher);
		adder.pb(C); adder.pb(D);
		paste(adder, pusher);
		adder.clear();

		res = press(pusher);
		pusher.clear();

		if (res == i) builder.pb(D);
		else if (res == i + 1) builder.pb(B);
		else builder.pb(C);
	}

	// all the middles, done
	
	builder.pb(B);
	res = press(builder);
	if (res != n)
	{
		builder.back() = C;
		res = press(builder);
		if (res != n)
		{
			builder.back() = D;
		}
	}

	return builder;

	// last char
}

• Subtask 1: 5 / 5
• Subtask 2: 0 / 95