public function testAuxiliaryFunctions()
{
$this->specify("Get the minimum distance between two data array", function () {
$data = getDataWithMinimumDistance(array(1, 8, 9), array(3, 8, 11));
expect($data[0])->equals(1);
expect($data[1])->equals(8);
expect($data[2])->equals(9);
});
$this->specify("Get the distance between two values", function () {
$distance = getDistanceBetweenTwoValues(88, 98);
expect($distance)->equals(10);
});
$this->specify("Get the closest values by brute force algorithm", function () {
$data = getClosestPairBybruteForce(array(1, 8, 9), 3);
expect($data[0])->equals(1);
expect($data[1])->equals(8);
expect($data[2])->equals(9);
});
$this->specify("Get the closest values in split array by brute force algorithm", function () {
$data = getClosestPairInSplitArrayByBruteForce(array(3, 4, 10, 20, 40), 5, array(20, 10, 30));
expect($data[0])->equals(1);
expect($data[1])->equals(3);
expect($data[2])->equals(4);
});
}
/**
* Calculate the closest two values inside array by brute force or divide and conquer algorithm
* @param [Array] $array [Array input]
* @param [Number] $arraySize [Array input length]
* @return [Array] [Array output]
*/
function getClosestPair($array, $arraySize)
{
if ($arraySize <= 3) {
return getClosestPairBybruteForce($array, $arraySize);
}
$midIndex = ceil($arraySize / 2);
$midValue = $array[$midIndex];
$arrayByLeft = array_slice($array, 0, $midIndex);
$arrayByRight = array_slice($array, $midIndex, $arraySize - $midIndex);
sort($arrayByLeft);
sort($arrayByRight);
$dataByLeft = getClosestPair($arrayByLeft, $midIndex);
$dataByRight = getClosestPair($arrayByRight, $arraySize - $midIndex);
$minData = getDataWithMinimumDistance($dataByLeft, $dataByRight);
$arraySplit = array();
$arraySplitSize = 0;
for ($i = 0; $i < $arraySize; $i++) {
if (abs($array[$i] - $midValue) < $minData[0]) {
$arraySplit[$arraySplitSize] = $array[$i];
$arraySplitSize++;
}
}
return getDataWithMinimumDistance($minData, getClosestPairInSplitArrayByBruteForce($arraySplit, $arraySplitSize, $minData));
}
