Submission #1002597

#	Time	Username	Problem	Language	Result	Execution time	Memory
1002597		fryingduc	Combo (IOI18_combo)	C++17	100 / 100	23 ms	2108 KiB

combo

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

const int maxn = 2005;
const char buttons[] = {'A', 'B', 'X', 'Y'};
string guess_sequence(int n) {
    string ans;
    string s;
    char ft = 'A';
    if(press("AB")) ft = (press("A") ? 'A' : 'B');
    else ft = (press("X") ? 'X' : 'Y');
    
    string other;
    for(int i = 0; i < 4; ++i) {
        if(buttons[i] != ft) {
            other += buttons[i];
        }
    }
    ans += ft;
    for(int len = 2; len <= n; len++) {
        if(len == n) {
            for(int j = 0; j < 3; ++j) {
                s = ans + other[j];
                if(j == 2) return s;
                if(press(s) == n) return s;
            }
        }
        s = ans + other[0];
        for(int j = 0; j < 4; ++j) {
            if(buttons[j] == ft) continue;
            s = s + ans + other[1] + buttons[j];
        }
        int x = press(s) - (int)ans.size();
        if(!x) ans += other[2];
        else if(x == 1) ans += other[0];
        else ans += other[1];
    }
    return ans;
}

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