Submission #759376

#	Time	Username	Problem	Language	Result	Execution time	Memory
759376		raysh07	Combo (IOI18_combo)	C++17	100 / 100	26 ms	528 KiB

combo

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

std::string guess_sequence(int N) {
//   std::string p = "";
//   for (int i = 0; i < 4 * N; ++i) {
//     p += 'A';
//   }
//   int coins = press(p);
//   std::string S = "";
//   for (int i = 0; i < N; ++i) {
//     S += 'A';
//   }
//   return S;

    int n = N;

    vector <char> a = {'A', 'B', 'X', 'Y'};
    
    string ans = "";
    char first = 'A';
    string p = "AB";
    int c = press(p);
    if (c > 0){
        p = "A";
        c = press(p);
        if (c > 0) first = 'A';
        else first = 'B';
    } else {
        p = "X";
        c = press(p);
        if (c > 0) first = 'X';
        else first = 'Y';
    }
    
    vector <char> b;
    for (auto x : a) if (x != first) b.push_back(x);
    
    ans += first;
    if (n == 1) return ans;
    
    for (int i = 1; i < n - 1; i++){
        string go = "";
        for (int j = 0; j < 4; j++){
            go += ans;
            if (j == 0) go += b[0];
            else {
            	go += b[1];
            	go += b[j - 1];
            }
        }
        
        c = press(go);
        if (c == i) ans += b[2];
        else if (c == i + 1) ans += b[0];
        else ans += b[1];
    }
    
    
    p = ans + 'A' + ans + 'B';
    c = press(p);
    
    if (c == n) {
        p = ans + 'A';
        c = press(p);
        
        if (c == n) ans += 'A';
        else ans += 'B';
    } else {
        p = ans + 'X';
        c = press(p);
        
        if (c == n) ans += 'X';
        else ans += 'Y';
    }
    
    return ans;
}

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