Submission #926927

#	Time	Username	Problem	Language	Result	Execution time	Memory
926927		bobbilyking	Combo (IOI18_combo)	C++17	94 / 100	17 ms	1756 KiB

combo

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

std::string guess_sequence(int N) {
    vector<char> poss{'A', 'B', 'X', 'Y'};
    string cur;
    for (char c: poss) {
        string s; s += c;
        if (press(s)) {
            poss.erase(find(poss.begin(), poss.end(), c)); 
            cur = s;
            break;
        } 
    }

    auto dumbextend = [&]() {
        bool done = 0;
        for (int i = 0; i < 2; ++i) {
            cur += poss[i];
            if (press(cur) == cur.size()) {
                done = 1; break;
            } 
            cur.pop_back();
        }
        if (!done) cur += poss[2];
    };

    while (cur.size() < N) {
        // might not need this, but im scared of querying too mayn letters
        // dumbextend(); continue;
        if (cur.size() + 1 == N) dumbextend();
        else {
            string temp;
            temp += cur + poss[0];
            for (int j= 0 ; j < 3; ++j) temp += (cur + poss[1]) + poss[j];

            auto res = press(temp);
            if (res == cur.size()) cur += poss[2];
            else if (res == cur.size() + 1) cur += poss[0];
            else cur += poss[1];
        }
    }
    // cout << "WTF " << cur << endl;

    // cout << cur << " " << cur.size() << " " << N << endl;
    assert(cur.size() == N);
  return cur;
}

Compilation message (stderr)

combo.cpp: In lambda function:
combo.cpp:21:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   21 |             if (press(cur) == cur.size()) {
      |                 ~~~~~~~~~~~^~~~~~~~~~~~~
combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:29:23: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   29 |     while (cur.size() < N) {
      |            ~~~~~~~~~~~^~~
combo.cpp:32:28: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   32 |         if (cur.size() + 1 == N) dumbextend();
      |             ~~~~~~~~~~~~~~~^~~~
combo.cpp:39:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   39 |             if (res == cur.size()) cur += poss[2];
      |                 ~~~~^~~~~~~~~~~~~
combo.cpp:40:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   40 |             else if (res == cur.size() + 1) cur += poss[0];
      |                      ~~~~^~~~~~~~~~~~~~~~~
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:2:
combo.cpp:47:23: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   47 |     assert(cur.size() == N);
      |            ~~~~~~~~~~~^~~~

• Subtask 1: 5 / 5
• Subtask 2: 89 / 95