Submission #1295786

#	Time	Username	Problem	Language	Result	Execution time	Memory
1295786		Fatonim	Combo (IOI18_combo)	C++20	100 / 100	9 ms	480 KiB

combo

#include "combo.h"
#include <bits/stdc++.h>

using namespace std;

#define popcount(n) __builtin_popcountll(n)
#define clz(n) __builtin_clzll(n)

#define print(a) cerr << "[" << #a << " = " << (a) << "] "
#define dbg(a) cerr << __LINE__ << ": "; print(a); cerr << "\n"
#define sz(a) (int)((a).size()) 

string guess_sequence(int n) {

	if (n == 1) {
		if (press("A")) return "A";
		if (press("B")) return "B";
		if (press("X")) return "X";
		return "Y";
	}

	vector<string> v = {"A", "B", "X", "Y"};
	int cnt = 0;
	string s = "";
	int res = press("AB");
	if (res >= 1) {
		int res = press("A");
		if (res == 1) s += "A";
		else s += "B";
	}
	else {
		int res = press("X");
		if (res == 1) s += "X";
		else s += "Y";
	}
	vector<string> nv;
	for (auto x : v) {
		if (x == s) continue;
		nv.push_back(x);
	}
	v = nv;
	// dbg(s);

	for (int i = 1; i < n; ++i) {
		if (i == n - 1) {
			if (press(s + v[0]) - sz(s) == 1) s += v[0];
			else if (press(s + v[1]) - sz(s) == 1) s += v[1];
			else s += v[2];
			continue;
		}
		string p = s + v[0] + v[0] + s + v[0] + v[1] + s + v[0] + v[2] + s + v[1] + s[0];
		int res = press(p) - sz(s);
		if (res == 2) s += v[0];
		else if (res == 1) s += v[1];
		else s += v[2];
		// dbg(s);
	}


	return s;
}

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