Submission #310642

#	Time	Username	Problem	Language	Result	Execution time	Memory
310642		LucaDantas	Combo (IOI18_combo)	C++17	100 / 100	38 ms	600 KiB

combo

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

#define pb push_back
#define sz(a) (int)((a).size())

string guess_sequence(int n) {
	string p = "";
	vector<char> dif;
	if(press("AB")) {
		if(press("A")) p = "A";
		else p = "B";
	}
	else if(press("X")) p = "X";
	else p = "Y";
	for(char c : {'A','B','X','Y'})
		if(c != p[0])
			dif.pb(c);
	for(int i = 1; i < n-1; i++) {
		string q = p;
		q.pb(dif[0]);
		for(int j = 0; j < 3; j++) {
			q += p;
			q.pb(dif[1]);
			q.pb(dif[j]);
		}
		int ans = press(q);
		if(ans == sz(p)) p.pb(dif[2]);
		else if(ans == sz(p)+1) p.pb(dif[0]);
		else p.pb(dif[1]);
	}
	bool ok = 0;
	for(int j = 0; j < 2; j++) {
		p.pb(dif[j]);
		if(press(p) == n) {ok = 1; break;};
		p.pop_back();
	}
	if(!ok) p.pb(dif[2]);
	return p;
}
*/

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

#define pb push_back
#define sz(a) (int)((a).size())

string guess_sequence(int N) {
	string p = "";
	vector<char> dif;
	if(press("AB")) {
		if(press("A")) p = "A";
		else p = "B";
	}
	else if(press("X")) p = "X";
	else p = "Y";
	for(char c : {'A','B','X','Y'})
		if(c != p[0])
			dif.pb(c);
	/*for(int i = 1; i < n; i++) {
		for(char c : dif) {
			p.pb(c);
			if(press(p) == sz(p)) break;
			p.pop_back();
		}
	}*/
	int last = 1;
	for(int i = 1; i < N-1; i++) {
		string q = "";
		q += p;
		q.pb(dif[1]);
		for(int j = 0; j < 3; j++) {
			q += p;
			q.pb(dif[0]);
			q.pb(dif[j]);
		}
		int ans = press(q);
		if(ans == sz(p)) p.pb(dif[2]);
		else if(ans == sz(p)+1) p.pb(dif[1]);
		else p.pb(dif[0]);
		assert(sz(p) - last == 1);
		last = sz(p);
	}
	if(sz(p) == N) return p;
	assert(sz(p) < N);
	// cout << p << '\n';
	for(int j = 0; j < 2; j++)
		if(press(p + dif[j]) == N) return p + dif[j];
	return p + dif[2];
}

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