jump_search.php

<?php
// PHP program to implement Jump Search

function jumpSearch($arr, $x, $n)
{
	// Finding block size to be jumped
	$step = sqrt($n);

	// Finding the block where element is
	// present (if it is present)
	$prev = 0;
	while ($arr[min($step, $n)-1] < $x)
	{
		$prev = $step;
		$step += sqrt($n);
		if ($prev >= $n)
			return -1;
	}

	// Doing a linear search for x in block
	// beginning with prev.
	while ($arr[$prev] < $x)
	{
		$prev++;

		// If we reached next block or end of
		// array, element is not present.
		if ($prev == min($step, $n))
			return -1;
	}
	// If element is found
	if ($arr[$prev] == $x)
		return $prev;

	return -1;
}

// Driver program to test function
$arr = array( 0, 1, 1, 2, 3, 5, 8, 13, 21,
				34, 55, 89, 144, 233, 377, 610 );
$x = 55;
$n = sizeof($arr) / sizeof($arr[0]);
	
// Find the index of '$x' using Jump Search
$index = jumpSearch($arr, $x, $n);

// Print the index where '$x' is located
echo "Number ".$x." is at index " .$index;
return 0;
?>