Submission #1051258

#	Time	Username	Problem	Language	Result	Execution time	Memory
1051258		thieunguyenhuy	Combo (IOI18_combo)	C++17	100 / 100	16 ms	2196 KiB

combo

#ifndef hwe
    #include "combo.h"
#endif

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

#define popcount(n) (__builtin_popcountll((n)))
#define clz(n) (__builtin_clzll((n)))
#define ctz(n) (__builtin_ctzll((n)))
#define lg(n) (63 - __builtin_clzll((n)))
#define BIT(n, i) (((n) >> (i)) & 1ll)
#define MASK(i) (1ll << (i))
#define FLIP(n, i) ((n) ^ (1ll << (i)))
#define ON(n, i) ((n) | MASK(i))
#define OFF(n, i) ((n) & ~MASK(i))

#define Int __int128
#define fi first
#define se second

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<long long, long long> pll;
typedef pair<long long, int> pli;
typedef pair<int, long long> pil;
typedef vector<pair<int, int>> vii;
typedef vector<pair<long long, long long>> vll;
typedef vector<pair<long long, int>> vli;
typedef vector<pair<int, long long>> vil;

template <class T1, class T2>
bool maximize(T1 &x, T2 y) {
    if (x < y) {
        x = y;
        return true;
    }
    return false;
}
template <class T1, class T2>
bool minimize(T1 &x, T2 y) {
    if (x > y) {
        x = y;
        return true;
    }
    return false;
}

template <class T>
void remove_duplicate(vector<T> &ve) {
    sort (ve.begin(), ve.end());
    ve.resize(unique(ve.begin(), ve.end()) - ve.begin());
}

mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
template <class T> T random(T l, T r) {
    return uniform_int_distribution<T>(l, r)(rng);
}
template <class T> T random(T r) {
    return rng() % r;
}

const int N = 1e6 + 5;
const int MOD = 1e9 + 7;
const int inf = 1e9;
const ll INF = 1e18;

string buttons[] = {"A", "B", "X", "Y"};

#ifdef hwe
int press(string p) {
    cerr << "Press: " << p << '\n';
    int ret; cin >> ret; return ret;
}
#endif

string guess_sequence(int n) {
    int first_idx = -1; string ans = "";
    
    if (press(buttons[0] + buttons[1])) {
        if (press(buttons[0])) first_idx = 0;
        else first_idx = 1;
    }
    else {
        if (press(buttons[2])) first_idx = 2;
        else first_idx = 3;
    }

    assert(first_idx != -1);
    ans = buttons[first_idx];

    if (n == 1) return ans;

    int x = -1, y = -1, z = -1;
    for (int i = 0; i < 4; ++i) {
        if (i == first_idx) continue;
        if (x == -1) x = i;
        else if (y == -1) y = i;
        else z = i;
    }

    for (int i = 2; i < n; ++i) {
        string query = (ans + buttons[x]) + (ans + buttons[y] + buttons[x]) + (ans + buttons[y] + buttons[y]) + (ans + buttons[y] + buttons[z]);
        int query_ans = press(query);
        assert(ans.size() <= query_ans && query_ans <= ans.size() + 2);
        if (query_ans == ans.size() + 1) ans += buttons[x];
        else if (query_ans == ans.size() + 2) ans += buttons[y];
        else ans += buttons[z];
    }

    // assert(press(ans) == n - 1);

    string query1 = ans + buttons[x], query2 = ans + buttons[y];
    if (press(query1) == n) return query1;
    if (press(query2) == n) return query2;
    return ans + buttons[z];
}

#ifdef hwe
signed main() {
    ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);

    int n; cin >> n;

    string ans = guess_sequence(n);
    cerr << "Guess: " << ans << '\n';

    cerr << '\n'; return 0;
}
#endif

Compilation message (stderr)

In file included from /usr/include/c++/10/cassert:44,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:33,
                 from combo.cpp:5:
combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:107:27: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
  107 |         assert(ans.size() <= query_ans && query_ans <= ans.size() + 2);
      |                ~~~~~~~~~~~^~~~~~~~~~~~
combo.cpp:107:53: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  107 |         assert(ans.size() <= query_ans && query_ans <= ans.size() + 2);
      |                                           ~~~~~~~~~~^~~~~~~~~~~~~~~~~
combo.cpp:108:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  108 |         if (query_ans == ans.size() + 1) ans += buttons[x];
      |             ~~~~~~~~~~^~~~~~~~~~~~~~~~~
combo.cpp:109:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  109 |         else if (query_ans == ans.size() + 2) ans += buttons[y];
      |                  ~~~~~~~~~~^~~~~~~~~~~~~~~~~

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