Submission #903908

#	Time	Username	Problem	Language	Result	Execution time	Memory
903908		zhasyn	Combo (IOI18_combo)	C++14	30 / 100	28 ms	1888 KiB

combo

#include "combo.h"
#include <bits/stdc++.h>
#define pb push_back
#define pf push_front
using namespace std;
#define F first
#define S second
typedef long long ll;
#define pii pair <int, int>
#define pll pair <ll, ll>
typedef long double ld;
const ll N = 2 * 1e5 + 10, len = 316;
const ll mod = 1e9 + 7;

ll um(ll a, ll b){
	return ((1LL * a * b) % mod + mod) % mod;
}
ll subr(ll a, ll b){
	return ((1LL * a - b) % mod + mod) % mod;
}
string check, s = "ABXY";
int fir, n1, n2, n3;
void create(int cur, int sz, string next){
	if(cur == sz){
		check += next;
		return;
	}
	create(cur + 1, sz, next + s[n1]);
	create(cur + 1, sz, next + s[n2]);
}
string guess_sequence(int n){
	n1 = n2 = n3 = -1;
	if(press("AB") >= 1){
		if(press("A") == 1) fir = 0;
		else fir = 1;
	} else{
		if(press("X") == 1) fir = 2;
		else fir = 3;
	}
	string ans = "";
	ans += s[fir];
	int cur = 1;
	for(int i = 0; i < 4; i++){
		if(i == fir) continue;
		if(n1 == -1) n1 = i;
		else{
			if(n2 == -1) n2 = i;
			else n3 = i;
		}
	}
	while(cur < n){
		int sz = cur, cnt = 1;
		while(true){
			if((sz + 1) * cnt * 2 > 4 * n || sz + 1 > n){
				check = "";
				create(cur, sz, ans);
				int res = press(check);
				while(cur < res){
					if(press(ans + s[n1]) == cur + 1){
						ans += s[n1];
					} else ans += s[n2];
					cur++;
				}
				if(res < sz){
					ans += s[n3];
					cur++;
				}
				break;
			}
			sz++;
			cnt *= 2;
		}
	}
	return ans;
}

• Subtask 1: 5 / 5
• Subtask 2: 25 / 95