PHP implementation for LIS (#2669)

Update LIS.php

Longest_Increasing_Subsequence/LIS.php

@@ -0,0 +1,43 @@
+<?php
+// PHP Implementation of LIS using Dynamic Programming
+
+// fumction to return the length of LIS
+function lisLen($arr, $n){
+
+    // length of LIS ending at index 0 is 1
+    $dp[0] = 1;
+
+    // compute the length of LIS ending at each index 
+    for ($i = 1; $i < $n; $i++){ 
+        $dp[$i] = 1; 
+        for ($j = 0; $j < $i; $j++)   
+            if ($arr[$i] > $arr[$j] && $dp[$i] < $dp[$j] + 1)  
+                $dp[$i] = $dp[$j] + 1;  
+    } 
+
+    // find the max out of computed lengths of LIS 
+    // ending at different indices
+    $max = PHP_INT_MIN;
+    for($i = 0; $i < $n; $i++){
+        if($max < $dp[$i])
+            $max = $dp[$i];
+    }
+
+    return $max;
+}
+
+// Sample test case
+$arr = array(3, 10, 2, 1, 20, 40, 60, 7);
+$n = sizeof($arr);
+
+echo "Length of LIS is " , lisLen($arr, $n);
+
+/*
+Sample Input as specified in the code:
+3, 10, 2, 1, 20, 40, 60, 7
+
+Sample Output:
+Length of LIS is 5
+*/
+
+?>