Submission #1147329

#	Time	Username	Problem	Language	Result	Execution time	Memory
1147329		minh30082008	Combo (IOI18_combo)	C++20	100 / 100	7 ms	488 KiB

combo

#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <string>
#include "combo.h"

#include<bits/stdc++.h>
#define INF 1e18
#define fi first
#define se second
#define FOR(i, k, n) for(ll i = k; i <= n; i++)
#define FOR1(i, k, n) for(ll i = k; i >= n; i--)
#define pb push_back
#define fastio ios::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define vi vector<int>
#define pii pair<int, int>
#define vii vector<pii>
#define ll long long
#define vll vector<ll>
#define pll pair<ll, ll>
#define re return 0
#define mii map<int, int>
#define input "chinaflu.inp"
#define output "chinaflu.out"
#define rf 	freopen(input, "r", stdin); freopen(output, "w", stdout)
using namespace std;
const int maxn = 3e5 + 5;
const int mod = 1e9 + 9;
const int base = 998244353;
void add(int &a, int b) 
{
	a += b; 
	if(a >= mod) a -= mod; 
	if(a < 0) a += mod; 
}
mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());
int rand(int l, int r)
{
	return uniform_int_distribution<int>(l, r) (rd);
}
string guess_sequence(int n)
{
	string P = "";
	int k = press("AB");
	if(k)
	{
		k = press("A");
		if(k)
			P += 'A';
		else
			P += 'B';
	}
	else
	{
		k = press("X");
		if(k)
			P += 'X';
		else
			P += 'Y';
	}
	n--;
	vector<char> vv;
	vv.clear();
	if('A' != P[0])
		vv.pb('A');
	if('B' != P[0])
		vv.pb('B');
	if('X' != P[0])
		vv.pb('X');
	if('Y' != P[0])
		vv.pb('Y');
	while(true)
	{
		if(!n)
			return P;
		if(n == 1)
		{
			string ask = P;
			ask += vv[0];
			k = press(ask);
			if(k > (int)P.size())
			{
				P += vv[0];
				return P;
			}
			ask = P;
			ask += vv[1];
			k = press(ask);
			if(k == (int)P.size() + 1)
			{
				P += vv[1];
				return P;
			}
			P += vv[2];
			return P;
		}
		string ask = "";
		ask += P;
		ask += vv[0];
		ask += vv[1];
		ask += P;
		ask += vv[0];
		ask += vv[0];
		ask += P;
		ask += vv[0]; 
		ask += vv[2];
		ask += P;
		ask += vv[1];
		k = press(ask);
		int cnt = P.size();
		if(k == cnt + 2)
			P += vv[0];
		if(k == cnt + 1)
			P += vv[1];
		if(k == cnt)
			P += vv[2];
		n--;
	}
}

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