39 lines
887 B
PHP
39 lines
887 B
PHP
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<?php
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$input_file = '../inputs/day1.txt';
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if (file_exists($input_file)) {
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$input = file_get_contents($input_file);
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if ($input != null) {
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$nums = array_map(fn ($str) => (int)$str, array_filter(explode("\n", $input), 'is_numeric'));
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print 'Part 1 answer: ' . solve_part_one($nums) . "\n";
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print 'Part 2 answer: ' . solve_part_two($nums) . "\n";
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}
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}
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function solve_part_one(array $nums): int
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{
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for ($i = 0; $i < count($nums); $i++) {
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for ($j = 0; $j < count($nums); $j++) {
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if ($nums[$i] + $nums[$j] == 2020) {
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return $nums[$i] * $nums[$j];
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}
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}
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}
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return 0;
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}
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function solve_part_two(array $nums): int
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{
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for ($i = 0; $i < count($nums); $i++) {
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for ($j = 0; $j < count($nums); $j++) {
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for ($k = 0; $k < count($nums); $k++) {
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if ($nums[$i] + $nums[$j] + $nums[$k] == 2020) {
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return $nums[$i] * $nums[$j] * $nums[$k];
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}
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}
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}
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}
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return 0;
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}
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