What is Calculate Combination using Factorial Method in PHP?

In this article, we will learn Calculate Combination using Factorial Method in PHP,This free PHP tutorial for complete beginners will help you learn PHP from scratch.

Calculate Combination using Factorial Method in PHP

What is nCr Formula?

Calculate Combination using Iterative Method in PHP

In this approach, we use factorial method to calculate the Combination i.e. nCr. The formula to calculate the combination is nCr = n! / (r! * (n-r)!).

Example:

PHP

<?php 
  
// Function to calculate factorial 
function factorial($n) { 
    if ($n == 0 || $n == 1) { 
        return 1; 
    } else { 
        return $n * factorial($n - 1); 
    } 
} 
  
// Function to calculate combination 
function combination($n, $r) { 
    if ($n < $r) { 
        return "Invalid input"; 
    } 
  
    return factorial($n) / (factorial($r) * factorial($n - $r)); 
} 
  
// Driver code 
$n = 5; 
$r = 2; 
  
echo "Combination: " . combination($n, $r); 
  
?>

Output

Combination: 10

PHP Program to Calculate Combination nCr

This article will show you how to Calculate the Combination nCr in PHP.

Combinations refer to the different ways in which a set of items can be selected without considering the order. In mathematics, the number of combinations of ‘n’ distinct items taken ‘r’ at a time is denoted as nCr. The formula for combinations is nCr = n! / (r! * (n-r)!), where ‘!’ denotes the factorial of a number.