Submission #713755

#	Time	Username	Problem	Language	Result	Execution time	Memory
713755		becaido	Combo (IOI18_combo)	C++17	100 / 100	39 ms	568 KiB

combo

#pragma GCC optimize("O3,unroll-loops")
#include <bits/stdc++.h>
#include "combo.h"
using namespace std;

#ifdef WAIMAI
#define debug(HEHE...) cout << "[" << #HEHE << "] : ", dout(HEHE)
void dout() {cout << '\n';}
template<typename T, typename...U>
void dout(T t, U...u) {cout << t << (sizeof... (u) ? ", " : ""), dout (u...);}
#else
#define debug(...) 7122
#endif

#define ll long long
#define Waimai ios::sync_with_stdio(false), cin.tie(0)
#define FOR(x,a,b) for (int x = a, I = b; x <= I; x++)
#define pb emplace_back
#define F first
#define S second

// times : N+2
string code[] = {"A", "B", "X", "Y"};
string guess_sequence(int N) {
    string cur;
    auto ask_one = [&]() {
        int len;
        len = press(cur + code[0] + cur + code[1]);
        if (len > cur.size()) {
            len = press(cur + code[0]);
            return len > cur.size() ? code[0] : code[1];
        } else {
            len = press(cur + code[2]);
            return len > cur.size() ? code[2] : code[3];
        }
    };
    cur = ask_one();
    for (int i = 0; i < 4; i++) if (code[i][0] == cur[0]) swap(code[0], code[i]);
    for (int i = 2; i < N; i++) {
        string ask = cur + code[1] + code[1] + cur + code[1] + code[2] + cur + code[1] + code[3] + cur + code[2];
        int len = press(ask);
        if (len == cur.size() + 2) cur += code[1];
        else if (len == cur.size() + 1) cur += code[2];
        else cur += code[3];
    }
    if (N > 1) cur += ask_one();
    return cur;
}

Compilation message (stderr)

combo.cpp: In lambda function:
combo.cpp:29:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   29 |         if (len > cur.size()) {
      |             ~~~~^~~~~~~~~~~~
combo.cpp:31:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   31 |             return len > cur.size() ? code[0] : code[1];
      |                    ~~~~^~~~~~~~~~~~
combo.cpp:34:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   34 |             return len > cur.size() ? code[2] : code[3];
      |                    ~~~~^~~~~~~~~~~~
combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:42:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   42 |         if (len == cur.size() + 2) cur += code[1];
      |             ~~~~^~~~~~~~~~~~~~~~~
combo.cpp:43:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   43 |         else if (len == cur.size() + 1) cur += code[2];
      |                  ~~~~^~~~~~~~~~~~~~~~~

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