PHP SplHeap top() Function

The SplHeap::top() function is an inbuilt function in PHP that is used to display the peek node from the top of the heap.

Generally, the Heap Data Structure is of two types

• Max-Heap: In a Max-Heap, the key present at the root node must be greatest among the keys present at all of its children. The same property must be recursively true for all sub-trees in that Binary Tree.
• Min-Heap: In a Min-Heap, the key present at the root node must be minimum among the keys present at all of its children. The same property must be recursively true for all sub-trees in that Binary Tree.

Syntax:

mixed SplHeap::top()

Parameters: This function does not accept any parameter.

Return Value: This function returns the value of the node on the top. 

Below programs illustrate the SplHeap::top() function in PHP.

Example 1:

PHP

<?php

// Create a new empty Min Heap
$heap = new SplMinHeap();

// Insert the elements into the heap
$heap->insert('System');
$heap->insert('GFG');
$heap->insert('ALGO');
$heap->insert('C');
$heap->insert('Geeks');
$heap->insert('GeeksforGeeks');

// Display the top element
var_dump($heap->top());

?>

Output:

string(4) "ALGO"

Example 2:

PHP

<?php

// Create a new empty Max Heap
$heap = new SplMaxHeap();

$heap->insert('System'.'<br/>');
$heap->insert('GFG'.'<br/>');
$heap->insert('ALGO'.'<br/>');
$heap->insert('C'.'<br/>');
$heap->insert('Geeks'.'<br/>');
$heap->insert('GeeksforGeeks'.'<br/>');

// Loop to display the current element of heap
for ($heap->top(); $heap->valid(); $heap->next())
{
    echo $heap->current() . "\n";
}

?>

Output:

System
GeeksforGeeks
Geeks
GFG
C
ALGO

Reference: https://www.php.net/manual/en/splheap.top.php