Field Notes

Building and Printing an N-Ary Tree in PHP

Recently a friend of mine asked me to help out on a trivial problem of building and printing an N-Ary Tree in PHP. I have posted this solution for a quick reference.


<?php
    //Data (Generally fetched from DB)
	$arr=array(         
		array("id" =>1, "parent_id"  =>0, "name"  =>"India"),
		array("id" =>2, "parent_id"  =>1, "name"  =>"North"),
		array("id" =>3, "parent_id"  =>1, "name"  =>"East"),
		array("id" =>4, "parent_id"  =>1, "name"  =>"South"),
		array("id" =>5, "parent_id"  =>1, "name"  =>"West"),
		array("id" =>6, "parent_id"  =>2, "name"  =>"Delhi"),
		array("id" =>7, "parent_id"  =>3, "name"  =>"Bihar"),
		array("id" =>8, "parent_id"  =>2, "name"  =>"Hariyana"),
		array("id" =>9, "parent_id"  =>5, "name"  =>"Goa"),
		array("id" =>10, "parent_id" =>4 , "name" =>"Andhra Pradesh"),
		array("id" =>11, "parent_id" =>3 , "name" =>"Jharkhand"),
		array("id" =>12, "parent_id" =>5 , "name" =>"Gujrat"),
		array("id" =>13, "parent_id" =>4 , "name" =>"Karnataka")
                                          
	);

	
	//tree construction algo
	function buildTree(&$elements, $parent_id=0) {
		$branch  = array();
		foreach($elements as $node) {
			if($node['parent_id']==$parent_id) {
				$children = buildTree(&$elements, $node['id']); 
				if($children) {
					$node['children'] = $children;
				}
				$branch[] = $node;
			}
		}
		return $branch;
	}
	
	//print tree algo
	function printTree($tree) {
		foreach($tree as $node) {
			echo "<li><a href='#'>".$node['name']."</a>";
			if(isset($node['children'])) {
				echo "<ul>";
				printTree($node['children']);
				echo "</ul>";
			}
			echo "</li>";
		}
	}
	
	
	$tree = buildTree($arr);

?>
<!DOCTYPE html>
<html>
	<head>
		<title>Printing a Tree in PHP</title>
	</head>
	<body>
		<ul>
			<?php echo printTree($tree); ?>
		</ul>
	</body>
</html>

Output:

India
- North
  - Delhi
  - Hariyana
- East
  - Bihar
  - Jharkhand
- South
  - Andhra Pradesh
  - Karnataka
- West
  - Goa
  - Gujrat

0 Comments

Split an integer in an array
Problem:

Split an integer into an array without converting it into a string. The order of integers should be properly maintained. e.g: for an integer 123, the array should be like [1, 2, 3].

(I heard about this problem from one of my friend, this question was asked to him in an interview. Here is my solution in JavaScript. I have taken the liberty to assume the numbers will be of base 10 for now.)

Solution:
```
 var test = 123 ,temp = 0 ,arr = [];
 while( test !== 0){
 temp = test % 10;
 arr.unshift(temp);
 test = Math.floor(test/10);
 }
 console.log(arr);
 
 
output:
[1, 2, 3]
```
0 Comments
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Part 1

Part 2

Part 3

Part 4

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Access GUI applications in a remote Linux system using SSH

Prerequisite:

You should be using any Linux / Unix terminal to accomplish this.

Step 1: Connect to the remote Linux system using SSH

$> ssh -Y username@hostname

password: *******

Step 2: Launch an application

$> firefox

You will see the firefox browser pops up.

Source: techyquest.blogspot.in
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11 Comments