Submission #171702

#	Time	Username	Problem	Language	Result	Execution time	Memory
171702		triple_fault	Combo (IOI18_combo)	C++14	100 / 100	52 ms	600 KiB

combo

#include "combo.h"
#include <vector>

std::string guess_sequence(int N) {
    std::string S = "";
    std::string fc = "";
    
    if (press("AB")) {
        if (press("A")) fc = "A";
        else fc = "B";
    } else {
        if (press("X")) fc = "X";
        else fc = "Y";
    }
    S = fc;

    std::vector<std::string> oops = {"A", "B", "X", "Y"}; 
    std::vector<std::string> chars;
    for (auto &each: oops) 
        if (each != fc) chars.push_back(each);

    for (int n = 2; n < N; ++n) {
        std::string p = "";
        p += S + chars[0] + S + chars[1] + chars[0] + S + chars[1] + chars[1] 
            + S + chars[1] + chars[2];
        int ret = press(p);
        if (ret == n) S += chars[0];
        else if (ret == (n + 1)) S += chars[1];
        else S += chars[2];
    }

    std::string p1 = S; std::string p2 = S;
    if (N > 1) {
        p1 += chars[0];
        p2 += chars[1];
    }
    if (press(p1) == N) return p1;
    else if (press(p2) == N) return p2;
    else if (N > 1) return S + chars[2];
    else return S;
}

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