3 points

How to find the nth Magic Number?


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Wed Dec 25 2019 13:48:42 GMT+0000 (UTC)

Posted by @marshmellow #php #interviewquestions #makethisbetter

<?php 
// PHP program to find nth 
// magic number 

// Function to find nth 
// magic number 
function nthMagicNo($n) 
{ 
	$pow = 1; 
	$answer = 0; 

	// Go through every bit of n 
	while ($n) 
	{ 
	$pow = $pow * 5; 

	// If last bit of n is set 
	if ($n & 1) 
		$answer += $pow; 

	// proceed to next bit 
	$n >>= 1; // or $n = $n/2 
	} 
	return $answer; 
} 

// Driver Code 
$n = 5; 
echo "nth magic number is ", 
	nthMagicNo($n), "\n"; 

// This code is contributed by Ajit. 
?> 
content_copy Copy

A magic number is defined as a number which can be expressed as a power of 5 or sum of unique powers of 5. First few magic numbers are 5, 25, 30(5 + 25), 125, 130(125 + 5), …. This is how to write a function that finds the nth Magic number.

https://www.geeksforgeeks.org/find-nth-magic-number/