Example: Solve 0/1 Knapsack Problem in PHP

<?php
// Solve 0/1 Knapsack Problem in PHP

// This will return max size of the value
function maxSize($a, $b) {
    return $a > $b ? $a : $b;
}

// This function will solve the 0 1 knapsack problem
function solveKnapSack($W, $wt = [], $val = [], $n) {
    if ($n == 0 || $W == 0) {
        return 0;
    }
    
	// 1. If the weight of the nth item is more than
	// 2. Knapsack capacity W, then this item cannot be included in the optimal solution
	if ($wt[$n - 1] > $W) {
	    return solveKnapSack($W, $wt, $val, $n - 1);
	}

	// It returns the maximum of two cases:
	// 1. nth item included
	// 2. not included
	else {
	    return maxSize($val[$n - 1] + solveKnapSack($W - $wt[$n - 1], $wt, $val, $n - 1), solveKnapSack($W, $wt, $val, $n - 1));
	}
}

// It's the driver code
$val = [60, 100, 120];
$wt  = [10, 20, 30];
$W   = 50;

$n = intval (sizeof($val) / sizeof($val[0]));

// This will print the solution of 0-1 Knapsack problem
echo "The solution of 0-1 Knapsack problem is: " . solveKnapSack($W, $wt, $val, $n);
?>