Codewars Kata

stats.php

<?php
/*
* You are the "computer expert" of a local Athletic Association (C.A.A.). Many teams of runners come to compete.
* Each time, you get a string of all race results of every team who has run.
* For example, here is  string showing the individual results of a team of 5 runners: "01|15|59, 1|47|6, 01|17|20, 1|32|34, 2|3|17"
* Each part of the string is of the form: h|m|s where h,m,s (h for hour, m for minutes, s for seconds) are positive or null integers,
* (represented as strings) with one or two digits. There are no traps in this format.
* To compare the results of the teams you are asked for giving three statistics; range, average and median
*
* Range: difference between the lowest and highest values. In {4, 6, 9, 3, 7}, the lowest value is 3 and highest is 9 so the range is 9 - 3 = 6
*
* Mean or Average: To calculate the mean, add together all of the numbers in the set and then divide the sum by the total count of the numbers
*
* Median: In statistics, the median is the number separating the higher half of a data sample from the lower half.
* The median of a finite list of numbers can be found by arranging all the observations from the lowest value to the highest value and
* picking the middle one (e.g. the median of {3, 3, 5, 9, 11} is 5) when there is an odd number of observations.
* If there is an even number of observations, then there is no single middle value; the median is then defined to be the mean of the two
* middle values (the median of {3, 5, 6, 9} is (5 + 6) / 2 = 5.5).
*
* Your task is to return a string giving these 3 values. For the example given above, the string result will be:
* "Range: 00|47|18 Average: 01|35|15 Median: 01|32|34" of the form: "Range: hh|mm|ss Average: hh|mm|ss Median: hh|mm|ss"
* where hh, mm, ss are integers (represented by strings) with each 2 digits
*
* Remarks:
* 1. If a result in seconds is ab.xy..., it will be given truncated as ab.
* 2. If the given string is "" you will return "".
*
*/


// Adding zeros in the right place to properly format time strings
function add_leading_zero ($number) {
	return ($number <= 9) ? '0' . $number : $number;
};

// convert time from hh|mm|ss to seconds and vice versa
function two_way_time_convert ($time) {
	// check for hh|mm|ss $time format
	if(preg_match('/(\w{1,2})\|(\w{1,2})\|(\w{1,2})/', $time)) {
		// convert from hh|mm|ss to seconds
		$timeArray = explode("|", $time);
		return ($timeArray[0] * 3600) + ($timeArray[1] * 60) + $timeArray[2];
	} else {
		// convert from seconds to hh|mm|ss
		$hr = floor($time / 3600);
		$min = floor(($time - ($hr * 3600)) / 60);
		$sec = $time - ($hr * 3600) - ($min * 60);
		return add_leading_zero($hr) . '|' . add_leading_zero($min) . '|' . add_leading_zero($sec);
	}
};

// median function
function medianValue($given_array) {
	// checking if length of array is even
	if (count($given_array) % 2 === 0) {
		// find the average of the 2 center numbers
		$half = floor((count($given_array) / 2));
		$med1 = $given_array[$half - 1];
		$med2 = $given_array[$half];
		return two_way_time_convert((($med1 + $med2) / 2));
	} else {
		// return the number at the center
		$half = floor(count($given_array) / 2);
		return two_way_time_convert($given_array[$half]);
	}
}

// Main function
function stats($stat_string) {
	// Check string length
	if (strlen($stat_string) === 0) {
		return "";
	} else {
		$time_array = explode(",", $stat_string);
		$time_array_converted = [];
		foreach ($time_array as $time_string) {
			array_push($time_array_converted, two_way_time_convert($time_string));
		}
		sort($time_array_converted);
		$mean = two_way_time_convert(floor(array_sum($time_array_converted) / count($time_array_converted)));
		$range = two_way_time_convert(max($time_array_converted) - min($time_array_converted));
		$median = medianValue($time_array_converted);
		return "Range: $range Average: $mean Median: $median";
	}
}

echo stats("01|15|59, 1|47|6, 01|17|20, 1|32|34, 2|3|17");

// Output: Range: 00|47|18 Average: 01|35|15 Median: 01|32|34