Submission #445483

#	Time	Username	Problem	Language	Result	Execution time	Memory
445483		silverfish	Combo (IOI18_combo)	C++14	100 / 100	42 ms	624 KiB

combo

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

#define pb push_back
#define ar array


string guess_sequence(int n) {
	srand(time(0));
	string ans="";
	vector<char> c, cc = {'A', 'B', 'X', 'Y'};
	char first;


	int ret = press(ans+cc[0]+cc[1]);
	if(ret == 0){
		ret = press(ans+cc[3]);
		if(ret == 1){
			first = cc[3];
		}else first = cc[2];
	}else{
		ret = press(ans+cc[0]);
		if(ret == 1){
			first = cc[0];
		}else first = cc[1];
	}
	ans += first;
	for(char ch : cc){
		if(ch != first) c.pb(ch);
	}

	for(int i = 1; i < n; ++i){
		random_shuffle(c.begin(), c.end());
		if(i == n-1){
			int ret = press(ans+c[0]);
			if(ret == i+1){
				ans.pb(c[0]);
			}else{
				ret = press(ans+c[1]);
				if(ret == i+1){
					ans.pb(c[1]);
				}else ans.pb(c[2]);
			}
			break;
		}
		ar<string,4> ask;
		ask[0] = {c[0], c[0]}; 
		ask[1] = {c[0], c[1]};
		ask[2] = {c[0], c[2]}; 
		ask[3] = {c[1]};

		int ret = press(ans+ask[0]+ans+ask[1]
				+ans+ask[2]+ans+ask[3]);
		if(ret == i){
			ans += c[2];
		}else if(ret == i+1){
			ans += c[1];
		}else{
			ans += c[0];
		}
	}

	return ans;
}

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