Submission #489804

#	Time	Username	Problem	Language	Result	Execution time	Memory
489804		DAleksa	Combo (IOI18_combo)	C++17	100 / 100	30 ms	592 KiB

combo

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

using namespace std;

string guess_sequence(int n) {
	char f;
	string s;
	s = "AB";
	int Q = 0;
	int q = press(s);
	Q++;
	if(q == 2) f = 'A';
	else if(q == 1) {
		s = "A";
		Q++;
		if(press(s) == 1) f = 'A';
		else f = 'B';
	} else {
		s = "X";
		Q++;
		if(press(s) == 1) f = 'X';
		else f = 'Y';
	}
	char c[4] = {'A', 'B', 'X', 'Y'};
	if(f == 'B') swap(c[1], c[0]);
	else if(f == 'X') swap(c[2], c[0]);
	else if(f == 'Y') swap(c[3], c[0]);
	s = "";
	for(int i = 0; i < 4*n; i++) s += c[0];
	for(int i = 1; i < n-1; i++) {
		s[i] = s[i+n] = s[i+2*n] = c[1];
		s[i+1] = c[1];
		s[i+1+n] = c[2];
		s[i+1+2*n] = c[3];
		s[i+3*n] = c[2];
		Q++;
		int x = press(s);
		if(x == i+2) s[i] = s[i+n] = s[i+2*n] = s[i+3*n] = c[1];
		else if(x == i+1) s[i] = s[i+n] = s[i+2*n] = s[i+3*n] = c[2];
		else s[i] = s[i+n] = s[i+2*n] = s[i+3*n] = c[3];
	}
	if(n > 1) {
		s[n-1] = 'A';
		s[2*n-1] = 'B';
		s[3*n-1] = 'A';
		s[4*n-1] = 'B';
		Q++;
		q = press(s);
		if(q == n) {
			s[2*n-1] = s[4*n-1] = 'A';
			Q++;
			if(press(s) != n) s[n-1] = 'B';
		} else {
			s[n-1] = s[2*n-1] = s[3*n-1] = s[4*n-1] = 'X';
			Q++;
			if(press(s) != n) s[n-1] = 'Y';
		}
	}
	string t = "";
	for(int i = 0; i < n; i++) t += s[i];
	assert(Q <= n+2);
	return t;
}

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