Submission #1004383

#	Time	Username	Problem	Language	Result	Execution time	Memory
1004383		The_Samurai	Combo (IOI18_combo)	C++17	100 / 100	21 ms	1952 KiB

combo

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

int counter;

int ask(string t) {
    counter++;
    return press(t);
}

string guess_sequence(int n) {
    string s = "ABXY", ans = "";
    for (int i = 0; i < 3 and n == 1; i++) {
        string t = "";
        t += s[i];
        if (ask(t)) return t;
    }
    if (n == 1) return "Y";
    if (ask("AB") >= 1) {
        // if (press("A")) ans = "A";
        // else ans = "B";
        ans = (ask("A") ? "A" : "B");
    } else {
        // if (press("X")) ans = "X";
        // else ans = "Y";
        ans = (ask("X") ? "X" : "Y");
    }
    s.erase(find(s.begin(), s.end(), ans[0]));
    for (int i = 1; i < n - 1; i++) {
        string t = "";
        t += ans + s[0];
        t += ans + s[1] + s[0];
        t += ans + s[1] + s[1];
        t += ans + s[1] + s[2];
        int val = ask(t);
        if (val == ans.size()) ans += s[2];
        else if (val == ans.size() + 1) ans += s[0];
        else ans += s[1];
    }
    assert(counter == n);
    for (int i = 0; i < 2; i++) {
        ans += s[i];
        if (ask(ans) == ans.size()) break;
        ans.pop_back();
    }
    if (ans.size() != n) ans += s[2];
    return ans;
}

Compilation message (stderr)

combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:37:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   37 |         if (val == ans.size()) ans += s[2];
      |             ~~~~^~~~~~~~~~~~~
combo.cpp:38:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   38 |         else if (val == ans.size() + 1) ans += s[0];
      |                  ~~~~^~~~~~~~~~~~~~~~~
combo.cpp:44:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   44 |         if (ask(ans) == ans.size()) break;
      |             ~~~~~~~~~^~~~~~~~~~~~~
combo.cpp:47:20: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   47 |     if (ans.size() != n) ans += s[2];
      |         ~~~~~~~~~~~^~~~

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