Submission #484871

#	Time	Username	Problem	Language	Result	Execution time	Memory
484871		MohamedFaresNebili	Combo (IOI18_combo)	C++14	100 / 100	46 ms	9824 KiB

combo

#include <bits/stdc++.h>
#pragma GCC optimize ("Ofast")
#pragma GCC target ("avx2")
#include "combo.h"
 
        using namespace std;
 
        using ll  = long long;
        using vi  = vector<int>;
 
        #define pb push_back
        #define ff first
        #define ss second
        #define lb lower_bound
        #define all(x) (x).begin() , (x).end()

string p = "", lett = "ABXY"; int n;
        void solve(int i, int first) {
          	if(i == n) return;
            if(i == n - 1) {
				p+="x";
                for(int l = 0; l < 2; l++) {
                    if(l == first) continue;
                    p[i] = lett[l];
                    if(press(p) == n) return;
                }
                if(first == 2) {
                    p[i] = lett[3];
                    return;
                }
                else if(first == 3) {
                    p[i] = lett[2];
                    return;
                }
                else {
                    p[i] = lett[2];
                    if(press(p) == n) return;
                    p[i] = lett[3]; return;
                }
				return;
            }
            vector<char>ch;
            for(int l = 0; l < 4; l++) {
                if(l == first) continue;
                ch.pb(lett[l]);
            }
			string s = "";
            for(auto u: ch) s+=p+ch[0]+u;
            s += p; s+=ch[1];
			p+="x";
          	int u = press(s);
            if(u == i + 1) p[i] = ch[1];
            else if(u >= i + 2) p[i] = ch[0];
            else p[i] = ch[2];
            solve(i+1, first);
        }
 
		string guess_sequence(int N) {
            int first = -1; n = N;
			string s = "AB";
			int u = press(s);
			if(u >= 1) {
				s = "A";
				if(press(s)) first = 0;
				else first = 1;
			}
			else {
				s = "X";
				if(press(s)) first = 2;
				else first = 3;
			}
			p = lett[first];
 			solve(1, first);
            return p;
        }

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