Submission #603650

#	Time	Username	Problem	Language	Result	Execution time	Memory
603650		yuto1115	Combo (IOI18_combo)	C++17	100 / 100	32 ms	696 KiB

combo

#include "combo.h"
#include "bits/stdc++.h"
#define rep(i, n) for(ll i = 0; i < ll(n); ++i)
#define rep2(i, s, n) for(ll i = ll(s); i < ll(n); ++i)
#define rrep(i, n) for(ll i = ll(n)-1; i >= 0; --i)
#define pb push_back
#define eb emplace_back
#define all(a) a.begin(),a.end()
#define SZ(a) int(a.size())
using namespace std;
using ll = long long;
using P = pair<int, int>;
using vi = vector<int>;
using vvi = vector<vi>;
using vl = vector<ll>;
using vvl = vector<vl>;
using vb = vector<bool>;
using vvb = vector<vb>;
using vp = vector<P>;
using vvp = vector<vp>;
using vs = vector<string>;

string guess_sequence(int n) {
    const string S = "ABXY";
    string res;
    string rem;
    {
        int a = press("XY") > 0;
        int b = press(S.substr(a * 2 + 1, 1)) > 0;
        res.pb(S[a * 2 + b]);
        rep(i, 4) if (i != a * 2 + b) rem.pb(S[i]);
    }
    auto f = [&](int i, int j) -> string {
        string t = res;
        t.pb(rem[i]);
        t.pb(rem[j]);
        return t;
    };
    while (SZ(res) < n) {
        if (SZ(res) < n - 1) {
            int now = press(f(0, 0) + f(0, 1) + f(1, 0));
            if (now == SZ(res) + 2) {
                now = press(f(0, 0));
                if (now == SZ(res) + 2) res = f(0, 0);
                else if (now == SZ(res) + 1) res = f(0, 1);
                else res = f(1, 0);
            } else if (now == SZ(res) + 1) {
                now = press(f(1, 1));
                if (now == SZ(res) + 2) res = f(1, 1);
                else if (now == SZ(res) + 1) res = f(1, 2);
                else res = f(0, 2);
            } else {
                assert(now == SZ(res));
                res.pb(rem[2]);
            }
        } else {
            string t = res;
            t.pb(rem[0]);
            if (press(t) == n) {
                res.pb(rem[0]);
            } else {
                t.pop_back();
                t.pb(rem[1]);
                res.pb(press(t) == n ? rem[1] : rem[2]);
            }
        }
    }
    return res;
}

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