Adding transitive dependencies problem

Author: cs_matheus_feola

problems/transitive-dependencies/Readme.md

@@ -0,0 +1,35 @@
+# Transitive Dependencies
+
+A class that calculates how dependencies propagate between things such as classes in a program. One of the insidious things about dependencies is that they are transitive—if A depends on B and B depends on C, then A also depends on C. So, this code that calculates the full set of dependencies for a group of items. Example class for test:
+
+```php
+
+<?php
+
+require_once 'transitive-dependencies.php';
+
+ class Dependencies_Test {
+
+     public $dependencies;
+
+     public function __construct() {
+         $this->dependencies = new DependenciesList();
+     }
+
+     public function add_direct_test() {
+         $this->dependencies->add_direct('A', 'B,C');
+          $this->dependencies->add_direct('B', 'C,E');
+          $this->dependencies->add_direct('C', 'G');
+          $this->dependencies->add_direct('D', 'A,F');
+          $this->dependencies->add_direct('E', 'F');
+         $this->dependencies->add_direct('F', 'H');
+     }
+
+ }
+
+$test = new Dependencies_Test();
+$test->add_direct_test();
+$resultado = $test->dependencies->dependencies_for("A");
+
+//print dependencies array in screen
+var_dump($resultado);

solutions/php/transitive-dependencies.php

@@ -0,0 +1,55 @@
+<?php
+
+class DependenciesList
+{
+    //where the dependencies values are stored
+    public $dependencies_matrix;
+
+    public function __construct()
+    {
+        $this->dependencies_matrix = array();
+    }
+
+    public function add_direct($index, $dependencies)
+    {
+        $this->dependencies_matrix[$index] = explode(",", $dependencies);
+    }
+
+    public function dependencies_for($element)
+    {
+        //array where dependencies of the element parameter will be stored
+        $dependents = array();
+        //process get element dependencies
+        $process = $this->dependencies_matrix[$element];
+
+        while (!empty($process)) {
+
+            //get an item from process
+            $x = array_shift($process);
+
+            //if x is not element itself, and is not in dependents array
+            if ($x != $element && !in_array($x, $dependents)) {
+
+                //put in dependents array
+                $dependents[] = $x;
+
+                //if x exists in dependencies_matrix
+                if (array_key_exists($x, $this->dependencies_matrix)) {
+
+                    //break the next dependencies list in strings
+                    if (gettype($this->dependencies_matrix[$x]) == "array") {
+                        foreach ($this->dependencies_matrix[$x] as $key => $value) {
+                            array_push($process, $value);
+                        }
+                    }
+
+                    else {
+                        //put the x line in process
+                        array_push($process, array_values($this->dependencies_matrix[$x]));
+                    }
+                }
+            }
+        }
+        return $dependents;
+    }
+} //endclass