48 lines
1.2 KiB
PHP
48 lines
1.2 KiB
PHP
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<?php
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$input_file = '../inputs/day2.txt';
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if (file_exists($input_file)) {
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$input = file_get_contents($input_file);
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if ($input != null) {
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$passwords = explode("\n", $input);
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print 'Part 1 answer: ' . solve_part_one($passwords) . "\n";
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print 'Part 2 answer: ' . solve_part_two($passwords) . "\n";
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}
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}
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function solve_part_one(array $passwords): int
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{
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function solve_1(int $min, int $max, string $key, string $pass): int
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{
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$letters = array_count_values(str_split($pass));
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if (array_key_exists($key, $letters) && $letters[$key] >= $min && $letters[$key] <= $max)
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return 1;
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return 0;
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}
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return parse_passwords_and_solve($passwords, 'solve_1');
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}
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function solve_part_two(array $passwords): int
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{
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function solve_2(int $pos1, int $pos2, string $key, string $pass): int
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{
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if ($pass[$pos1 - 1] === $key xor $pass[$pos2 - 1] === $key)
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return 1;
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return 0;
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}
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return parse_passwords_and_solve($passwords, 'solve_2');
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}
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function parse_passwords_and_solve(array $passwords, callable $fun): int
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{
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$ret = 0;
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foreach ($passwords as $policy) {
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preg_match('/^(\d+?)-(\d+?) ([a-z]): (.+?)$/', $policy, $matches);
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[$match, $min, $max, $key, $pass] = $matches;
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if ($match)
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$ret += $fun($min, $max, $key, $pass);
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}
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return $ret;
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}
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