Submission #1189237

#	Time	Username	Problem	Language	Result	Execution time	Memory
1189237		Zakir060	Combo (IOI18_combo)	C++20	10 / 100	15 ms	440 KiB

combo

#include <string>
#include <vector>
#include <numeric> // Not strictly needed but good practice

// Forward declaration or include header provided by contest environment
// #include "combo.h"
extern int press(std::string p);

std::string guess_sequence(int N) {
    std::string guessed_S = "";
    std::vector<char> all_chars = {'A', 'B', 'X', 'Y'};

    if (N == 0) {
        return "";
    }

    // --- Step 1: Determine the first character S[0] ---
    // Try A
    if (press("A") == 1) {
        guessed_S = "A";
    } else if (press("B") == 1) { // Try B if A failed
        guessed_S = "B";
    } else {                     // If A and B failed, try X
        // If press("X") == 1, it's X. Otherwise, it must be Y.
        if (press("X") == 1) {
            guessed_S = "X";
        } else {
            guessed_S = "Y";
        }
    }

    // --- Step 2: Determine the remaining characters S[1] to S[N-1] ---
    while (guessed_S.length() < N) {
        int k = guessed_S.length();
        char next_char = 0; // To store the determined next character

        // Try appending 'A', 'B', 'X' one by one.
        // If press(current_guess + candidate) returns k+1, we found the next char.
        // If A, B, X don't work, the next char must be Y.

        if (press(guessed_S + 'A') == k + 1) {
            next_char = 'A';
        } else if (press(guessed_S + 'B') == k + 1) {
            next_char = 'B';
        } else if (press(guessed_S + 'X') == k + 1) {
            next_char = 'X';
        } else {
            next_char = 'Y'; // Must be Y if others failed
        }

        // Append the determined character
        // Using push_back might be slightly more efficient than += for single chars
        guessed_S.push_back(next_char);
    }

    return guessed_S;
}

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