Submission #581785

#	Time	Username	Problem	Language	Result	Execution time	Memory
581785		ddy888	Combo (IOI18_combo)	C++17	100 / 100	40 ms	628 KiB

combo

#include "combo.h"
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define fi first
#define se second
typedef pair<int,int> pi;
void debug_out() {cerr<<endl;}
template <typename Head, typename... Tail>
void debug_out(Head _H, Tail... _T) {cerr<<" "<<to_string(_H);debug_out(_T...);}
#define debug(...) cerr<<"["<<#__VA_ARGS__<<"]:",debug_out(__VA_ARGS__)

string ans;
string ch = "ABXY";
char rem[4];
int id;

string guess_sequence(int n) {
    int f = press("AB");
    if (f) {
        if (press("A")) ans += "A";
        else ans += "B";
    } else {
        if (press("X")) ans += "X";
        else ans += "Y";
    }
    
    for (int i = 0; i < 4; ++i) {
        if (ch[i] != ans[0]) {
            rem[++id] = ch[i];
        }
    }
    rem[0] = rem[id];
    if (n == 1) return ans;
    if (n == 2) goto last;

    for (int i = 2; i < n; ++i) {
        string guess = "";
        int cnt = 0;
        for (int j = 0; j < 4; ++j) {
            if (ans[0] == ch[j]) continue;
            ++cnt;
            if (cnt == 1) {
                guess += ans + ch[j];
            } else {
                for (int k = 0; k < 4; ++k) {
                    if (ans[0] == ch[k]) continue;
                    guess += ans + ch[j] + ch[k];
                }
                break;
            }
        }
        int res = press(guess) - (int)ans.size();
        ans += rem[res];
    }

    last:
    for (int i = 0; i < 2; ++i) {
        string guess = ans + rem[i];
        if (press(guess) == n) return guess;
    }
    ans += rem[2];

    return ans;
}

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