Submission #445480

#	Time	Username	Problem	Language	Result	Execution time	Memory
445480		silverfish	Combo (IOI18_combo)	C++14	97 / 100	36 ms	580 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'};
	bool found = 0;

	for(int i = 0; i < 3; ++i){
		if(press(ans+cc[i])){
			ans.pb(cc[i]);	
			for(char cch : cc) 
				if(cch != cc[i]) c.pb(cch);
			found = 1;
			break;
		}
	}
	if(!found){
		ans.pb(cc[3]);
		for(char cch : cc) 
			if(cch != cc[3]) c.pb(cch);
	}

	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: 92 / 95