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2015 Day 14 part 1 & 2 (#24)
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‎2015/day-14.php

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<?php
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ini_set("memory_limit", "-1");
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require __DIR__ . '/../vendor/autoload.php';
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use adventofcode\Year2015\ReindeerOlympics;
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/**
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* --- Day 14: Reindeer Olympics ---
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*
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* This year is the Reindeer Olympics! Reindeer can fly at high speeds, but must rest occasionally to recover their
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* energy. Santa would like to know which of his reindeer is fastest, and so he has them race.
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*
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* Reindeer can only either be flying (always at their top speed) or resting (not moving at all), and always spend
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* whole seconds in either state.
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*
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* For example, suppose you have the following Reindeer:
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*
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* - Comet can fly 14 km/s for 10 seconds, but then must rest for 127 seconds.
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* - Dancer can fly 16 km/s for 11 seconds, but then must rest for 162 seconds.
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*
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* After one second, Comet has gone 14 km, while Dancer has gone 16 km. After ten seconds, Comet has gone 140 km,
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* while Dancer has gone 160 km. On the eleventh second, Comet begins resting (staying at 140 km), and Dancer
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* continues on for a total distance of 176 km. On the 12th second, both reindeer are resting. They continue to
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* rest until the 138th second, when Comet flies for another ten seconds. On the 174th second, Dancer flies
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* for another 11 seconds.
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*
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* In this example, after the 1000th second, both reindeer are resting, and Comet is in the lead at 1120 km
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* (poor Dancer has only gotten 1056 km by that point). So, in this situation, Comet would win
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* (if the race ended at 1000 seconds).
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*
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* Given the descriptions of each reindeer (in your puzzle input), after exactly 2503 seconds, what distance
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* has the winning reindeer traveled?
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*/
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$reindeerOlympics = new ReindeerOlympics();
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$input = file(__DIR__ . '/inputs/day-14.input', FILE_IGNORE_NEW_LINES);
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$result = $reindeerOlympics->determineFlightWinnerDistance($input, 2503);
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print('The winning reindeer flew ' . $result . " kilometers.\n");
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/**
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* --- Part Two ---
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*
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* Seeing how reindeer move in bursts, Santa decides he's not pleased with the old scoring system.
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*
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* Instead, at the end of each second, he awards one point to the reindeer currently in the lead. (If there are
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* multiple reindeer tied for the lead, they each get one point.) He keeps the traditional 2503 second time limit,
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* of course, as doing otherwise would be entirely ridiculous.
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*
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* Given the example reindeer from above, after the first second, Dancer is in the lead and gets one point. He stays
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* in the lead until several seconds into Comet's second burst: after the 140th second, Comet pulls into the lead
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* and gets his first point. Of course, since Dancer had been in the lead for the 139 seconds before that, he has
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* accumulated 139 points by the 140th second.
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*
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* After the 1000th second, Dancer has accumulated 689 points, while poor Comet, our old champion, only has 312.
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* So, with the new scoring system, Dancer would win (if the race ended at 1000 seconds).
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*
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* Again given the descriptions of each reindeer (in your puzzle input), after exactly 2503 seconds, how many
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* points does the winning reindeer have?
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*/
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$result = $reindeerOlympics->determineFlightWinnerPoints($input, 2503);
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print('The winning reindeer accumulated ' . $result . " points.\n");

‎2015/inputs/day-14-sample.input

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Comet can fly 14 km/s for 10 seconds, but then must rest for 127 seconds.
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Dancer can fly 16 km/s for 11 seconds, but then must rest for 162 seconds.

‎2015/inputs/day-14.input

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Vixen can fly 19 km/s for 7 seconds, but then must rest for 124 seconds.
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Rudolph can fly 3 km/s for 15 seconds, but then must rest for 28 seconds.
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Donner can fly 19 km/s for 9 seconds, but then must rest for 164 seconds.
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Blitzen can fly 19 km/s for 9 seconds, but then must rest for 158 seconds.
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Comet can fly 13 km/s for 7 seconds, but then must rest for 82 seconds.
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Cupid can fly 25 km/s for 6 seconds, but then must rest for 145 seconds.
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Dasher can fly 14 km/s for 3 seconds, but then must rest for 38 seconds.
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Dancer can fly 3 km/s for 16 seconds, but then must rest for 37 seconds.
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Prancer can fly 25 km/s for 6 seconds, but then must rest for 143 seconds.

‎2015/src/ReindeerOlympics.php

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<?php
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namespace adventofcode\Year2015;
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class ReindeerOlympics
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{
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/**
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* Determine the maximum distance flown from a given set of reindeer.
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*
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* @param array $reindeerData
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* @param int $interval
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* @return float
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*/
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public function determineFlightWinnerDistance(array $reindeerData, int $interval): float
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{
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$winnersDistance = 0;
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foreach ($reindeerData as $reindeer) {
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$data = $this->parseReindeerData($reindeer);
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$distance = $this->calculateDistance(
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$data['speed'],
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$data['flightTime'],
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$data['oneSecondFlightDistance'],
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$data['restDuration'],
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$interval
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);
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if ($distance > $winnersDistance) {
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$winnersDistance = $distance;
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}
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}
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return $winnersDistance;
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}
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/**
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* Determine the winning points from a given set of reindeer.
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*
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* @param array $reindeerData
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* @param int $interval
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* @return int
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*/
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public function determineFlightWinnerPoints(array $reindeerData, int $interval): int
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{
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$contestants = [];
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foreach ($reindeerData as $reindeer) {
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$data = $this->parseReindeerData($reindeer);
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$contestants[] = $data;
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}
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for ($i = 0; $i < $interval; $i++) {
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// Determine each reindeer's current distance.
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foreach ($contestants as $index => $contestant) {
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if (!$contestant['isResting']) {
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$contestants[$index]['currentDistance'] += $contestant['speed'];
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if ($contestants[$index]['currentLeg'] + 1 === $contestant['flightTime']) {
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$contestants[$index]['isResting'] = true;
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$contestants[$index]['currentLeg'] = 0;
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continue;
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}
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$contestants[$index]['currentLeg']++;
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}
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if ($contestant['isResting'] && $contestant['currentRestTime'] + 1 === $contestant['restDuration']) {
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$contestants[$index]['isResting'] = false;
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$contestants[$index]['currentRestTime'] = 0;
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continue;
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}
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if ($contestant['isResting']) {
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$contestants[$index]['currentRestTime']++;
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}
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}
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// Find the largest current distance
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$largestDistance = 0;
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foreach ($contestants as $contestant) {
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if ($contestant['currentDistance'] > $largestDistance) {
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$largestDistance = $contestant['currentDistance'];
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}
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}
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// Update the scores for those in the lead.
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foreach ($contestants as $index => $contestant) {
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if ($contestant['currentDistance'] === $largestDistance) {
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$contestants[$index]['currentPoints']++;
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}
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}
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}
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$winnersPoints = 0;
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foreach ($contestants as $contestant) {
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if ($contestant['currentPoints'] > $winnersPoints) {
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$winnersPoints = $contestant['currentPoints'];
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}
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}
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return $winnersPoints;
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}
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/**
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* Find the distance covered over a given interval based on the given speed, flight time, and rest duration.
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* All values are in seconds.
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*
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* @param int $speed
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* @param int $flightTime
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* @param float $oneSecondFlightDistance
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* @param int $restDuration
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* @param int $interval
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* @return float
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*/
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protected function calculateDistance(
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int $speed,
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int $flightTime,
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float $oneSecondFlightDistance,
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int $restDuration,
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int $interval
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): float {
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$distance = 0;
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$maxFlightTime = $speed * $flightTime;
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$currentTime = 0;
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while ($currentTime < $interval) {
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if ($maxFlightTime > $interval) {
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$distance += $oneSecondFlightDistance * ($interval - $currentTime);
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$currentTime = $interval;
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continue;
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}
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if ($maxFlightTime + $restDuration > $interval) {
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$distance += $maxFlightTime + ($interval - $currentTime);
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$currentTime = $interval;
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continue;
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}
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$distance += $maxFlightTime;
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$currentTime += $flightTime + $restDuration;
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}
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return $distance;
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}
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/**
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* Parse a string of reindeer flight data.
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*
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* @param string $reindeer
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* @return array
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*/
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protected function parseReindeerData(string $reindeer): array
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{
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preg_match('/(.*) can fly (\d+) km\/s for (\d+).*for (\d+).*/', $reindeer, $matches);
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return [
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'name' => $matches[1],
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'speed' => intval($matches[2]),
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'flightTime' => intval($matches[3]),
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'oneSecondFlightDistance' => $matches[2] / $matches[3],
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'maxFlightTime' => $matches[2] * $matches[3],
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'restDuration' => intval($matches[4]),
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'currentDistance' => 0,
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'currentPoints' => 0,
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'currentLeg' => 0,
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'isResting' => false,
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'currentRestTime' => 0,
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];
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}
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}

‎2015/tests/ReindeerOlympicsTest.php

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<?php
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namespace adventofcode\Year2015\Test;
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use adventofcode\Year2015\ReindeerOlympics;
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use PHPUnit\Framework\TestCase;
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class ReindeerOlympicsTest extends TestCase
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{
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protected ReindeerOlympics $reindeerOlympics;
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protected array $sampleInput;
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protected array $input;
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protected function setup(): void
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{
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$this->reindeerOlympics = new ReindeerOlympics();
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$this->sampleInput = file(__DIR__ . '/../inputs/day-14-sample.input', FILE_IGNORE_NEW_LINES);
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$this->input = file(__DIR__ . '/../inputs/day-14.input', FILE_IGNORE_NEW_LINES);
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}
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public function testDetermineFlightWinnerDistance()
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{
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// Day 14 sample input
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$result = $this->reindeerOlympics->determineFlightWinnerDistance($this->sampleInput, 1000);
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$this->assertEquals(1120, $result);
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// Day 14 input
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$result = $this->reindeerOlympics->determineFlightWinnerDistance($this->input, 2503);
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$this->assertEquals(2660, $result);
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}
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public function testDetermineFlightWinnerPoints()
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{
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// Day 14 sample input
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$result = $this->reindeerOlympics->determineFlightWinnerPoints($this->sampleInput, 1000);
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$this->assertEquals(689, $result);
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// Day 14 input
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$result = $this->reindeerOlympics->determineFlightWinnerPoints($this->input, 2503);
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$this->assertEquals(1256, $result);
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}
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}

‎README.md

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| Day 11 | | | | | | | | | |
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| Day 12 | | | | | | | | | |
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| Day 13 | | | | | | | | | |
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| Day 14 | | | | | | | | | |
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| Day 14 | | | | | | | | | :star: :star: |
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| Day 15 | | | | | | | | | |
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| Day 16 | | | | | | | | | |
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| Day 17 | | | | | | | | | |

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