algorithms/coderun/0049.php at master · crystarm/algorithms · GitHub

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<?php

// https://coderun.yandex.ru/problem/hack-pentagon
// constructive algorithm

$line = fgets(STDIN);
if ($line === false) {
    exit();
}
$n = (int) trim($line);

$baseString = str_repeat("a", $n);

echo $baseString . "\n";
flush();

$response = fgets(STDIN);
if ($response === false) {
    exit();
}
$baseDist = (int) trim($response);

if ($baseDist === 0) {
    exit();
}

$password = "";

for ($i = 0; $i < $n; $i++) {
    $baseString[$i] = "z";

    echo $baseString . "\n";
    flush();

    $response = fgets(STDIN);
    if ($response === false) {
        exit();
    }
    $currentDist = (int) trim($response);

    if ($currentDist === 0) {
        exit();
    }

    $baseString[$i] = "a";

    $delta = $currentDist - $baseDist;
    $offset = (25 - $delta) / 2;

    $char = chr(ord("a") + (int) $offset);
    $password .= $char;
}

echo $password . "\n";
flush();

fgets(STDIN);