smaller fixes and improvements

doganoo · Nov 26, 2018 · 3096ed3 · 3096ed3
1 parent 0980ac5
commit 3096ed3
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Showing 9 changed files with 77 additions and 19 deletions.
diff --git a/src/Datastructure/Graph/Graph/Node.php b/src/Datastructure/Graph/Graph/Node.php
@@ -26,6 +26,7 @@
 namespace doganoo\PHPAlgorithms\Datastructure\Graph\Graph;
 
 use doganoo\PHPAlgorithms\Common\Interfaces\INode;
+use doganoo\PHPAlgorithms\Common\Util\Comparator;
 use doganoo\PHPAlgorithms\Datastructure\Lists\ArrayLists\ArrayList;
 
 /**
@@ -85,7 +86,7 @@ public function hasAdjacent(Node $node) {
          * @var Node $value
          */
         foreach ($this->adjacent as $key => $value) {
-            if ($value->getValue() == $node->getValue()) {
+            if (Comparator::equals($value->getValue(), $node->getValue())) {
                 return true;
             }
         }

diff --git a/src/Datastructure/Graph/Tree/Heap/MaxHeap.php b/src/Datastructure/Graph/Tree/Heap/MaxHeap.php
@@ -25,6 +25,7 @@
 
 namespace doganoo\PHPAlgorithms\Datastructure\Graph\Tree\Heap;
 
+use doganoo\PHPAlgorithms\Common\Exception\IndexOutOfBoundsException;
 use doganoo\PHPAlgorithms\Common\Interfaces\IHeap;
 use doganoo\PHPAlgorithms\Common\Util\Comparator;
 
@@ -65,6 +66,7 @@ public function clear(): bool {
 
     /**
      * @param int $element
+     * @throws IndexOutOfBoundsException
      */
     public function insert(int $element): void {
         $length = $this->length();
@@ -75,8 +77,15 @@ public function insert(int $element): void {
         $current = $this->heap[$currentPosition];
         $parent = $this->heap[$parentPosition];
 
+        //this could be implemented in recursive way as well!
         while (Comparator::greaterThan($current, $parent)) {
             $this->swap($currentPosition, $parentPosition);
+            //since we have swapped the positions, we need
+            //to redefine our current position and parent position
+            //and 'bubble up':
+            //the current position is the parent position and the
+            //parent position is the parent position of the current position
+            //(i know, it is confusing :-))
             $currentPosition = $this->getParentPosition($currentPosition);
             $parentPosition = $this->getParentPosition($currentPosition);
             $current = $this->heap[$currentPosition];
@@ -120,9 +129,11 @@ public function length(): int {
      *
      * @param int $pos
      * @return int
+     * @throws IndexOutOfBoundsException
      */
     public function getParentPosition(int $pos): int {
-        return $pos === 0 ? 0 : $pos / 2;
+        if ($pos < 0) throw new IndexOutOfBoundsException("$pos < 0");
+        return $pos === 0 ? 0 : \intval($pos / 2);
     }
 
     /**

diff --git a/src/Datastructure/Graph/Tree/Heap/MinHeap.php b/src/Datastructure/Graph/Tree/Heap/MinHeap.php
@@ -25,6 +25,7 @@
 
 namespace doganoo\PHPAlgorithms\Datastructure\Graph\Tree\Heap;
 
+use doganoo\PHPAlgorithms\Common\Exception\IndexOutOfBoundsException;
 use doganoo\PHPAlgorithms\Common\Interfaces\IHeap;
 use doganoo\PHPAlgorithms\Common\Util\Comparator;
 
@@ -65,6 +66,7 @@ public function clear(): bool {
 
     /**
      * @param int $element
+     * @throws IndexOutOfBoundsException
      */
     public function insert(int $element): void {
         $length = $this->length();
@@ -75,8 +77,15 @@ public function insert(int $element): void {
         $current = $this->heap[$currentPosition];
         $parent = $this->heap[$parentPosition];
 
+        //this could be implemented in recursive way as well!
         while (Comparator::lessThan($current, $parent)) {
             $this->swap($currentPosition, $parentPosition);
+            //since we have swapped the positions, we need
+            //to redefine our current position and parent position
+            //and 'bubble up':
+            //the current position is the parent position and the
+            //parent position is the parent position of the current position
+            //(i know, it is confusing :-))
             $currentPosition = $this->getParentPosition($currentPosition);
             $parentPosition = $this->getParentPosition($currentPosition);
             $current = $this->heap[$currentPosition];
@@ -120,9 +129,11 @@ public function length(): int {
      *
      * @param int $pos
      * @return int
+     * @throws IndexOutOfBoundsException
      */
     public function getParentPosition(int $pos): int {
-        return $pos === 0 ? 0 : $pos / 2;
+        if ($pos < 0) throw new IndexOutOfBoundsException("$pos < 0");
+        return $pos === 0 ? 0 : intval($pos / 2);
     }
 
     /**

diff --git a/src/Datastructure/Graph/Tree/Trie/Node.php b/src/Datastructure/Graph/Tree/Trie/Node.php
@@ -44,23 +44,45 @@ public function __construct() {
         $this->children = [];
     }
 
+    /**
+     * @param int $position
+     * @return bool
+     */
+    public function hasChild(int $position): bool {
+        return null !== $this->getChildNode($position);
+    }
+
+    /**
+     * @param int $position
+     * @return Node|null
+     */
     public function getChildNode(int $position): ?Node {
         if (isset($this->children[$position])) {
             return $this->children[$position];
         }
         return null;
     }
 
+    /**
+     * @param int $position
+     */
     public function createChildNode(int $position) {
         $node = new Node();
         $node->setValue($position);
         $this->children[$position] = $node;
     }
 
+    /**
+     * creates an node that indicates the end of the word
+     */
     public function createEndOfWordNode() {
         $this->children[] = new EndOfWordNode();
     }
 
+    /**
+     * indicates whether it is the end of the node
+     * @return bool
+     */
     public function isEndOfNode() {
         return $this->children[0] instanceof EndOfWordNode;
     }

diff --git a/src/Datastructure/Graph/Tree/Trie/Trie.php b/src/Datastructure/Graph/Tree/Trie/Trie.php
@@ -55,33 +55,44 @@ public function __construct() {
     public function insert(string $string) {
         $node = $this->root;
         for ($i = 0; $i < \strlen($string); $i++) {
-            $position = \ord($string[$i]) - \ord("a");
-            if (null === $node->getChildNode($position)) {
-                $node->createChildNode($position);
+            $charIndex = $this->getCharIndex($string[$i]);
+            if (!$node->hasChild($charIndex)) {
+                $node->createChildNode($charIndex);
             }
-            $node = $node->getChildNode($position);
+            $node = $node->getChildNode($charIndex);
         }
         $node->createEndOfWordNode();
     }
 
+    /**
+     * returns the ASCII value of $char - ASCII value of 'a'
+     *
+     * @param string $char
+     * @return int
+     */
+    private function getCharIndex(string $char): int {
+        if (\strlen($char) > 1) $char = \substr($char, 0, 1);
+        return \ord($char) - \ord('a');
+    }
+
     /**
      * searches for an string in the trie. $isPrefix indicates whether
      * the method should search for the entire word.
      *
      * @param string $key
-     * @param bool   $isPrefix
+     * @param bool $isPrefix
      * @return bool
      */
     public function search(string $key, bool $isPrefix = false): bool {
         $length = \strlen($key);
         $node = $this->root;
 
         for ($i = 0; $i < $length; $i++) {
-            $index = \ord($key[$i]) - \ord('a');
-            if (null === $node->getChildNode($index)) {
+            $charIndex = $this->getCharIndex($key[$i]);
+            if (!$node->hasChild($charIndex)) {
                 return false;
             }
-            $node = $node->getChildNode($index);
+            $node = $node->getChildNode($charIndex);
         }
         if ($isPrefix) {
             return null !== $node;

diff --git a/src/Datastructure/Lists/ArrayLists/StringBuilder.php b/src/Datastructure/Lists/ArrayLists/StringBuilder.php
@@ -162,7 +162,7 @@ private function arrayListToStringBuilder(ArrayList $arrayList, bool $reverse =
                 }
             }
             while (!$stack->isEmpty()) {
-                $stringBuilder->append($stack->peek());
+                $stringBuilder->append($stack->pop());
             }
         } else {
             $queue = new Queue();

diff --git a/src/Datastructure/Maps/HashMap.php b/src/Datastructure/Maps/HashMap.php
@@ -40,6 +40,7 @@
  * TODO implement entrySet
  * TODO implement values
  * TODO implement Java-like generics for key and value
+ * TODO replace LinkedList with BinarySearchTree
  * TODO (optional) implement universal hashing
  *
  * @package doganoo\PHPAlgorithms\Maps
@@ -221,7 +222,7 @@ public function getNodeByKey($key): ?Node {
     public function size(): int {
         $size = 0;
         /**
-         * @var string              $hash
+         * @var string $hash
          * @var  AbstractLinkedList $list
          */
         foreach ($this->bucket as $hash => $list) {
@@ -239,7 +240,7 @@ public function size(): int {
     public function containsValue($value): bool {
 
         /**
-         * @var string           $arrayIndex
+         * @var string $arrayIndex
          * @var SinglyLinkedList $list
          */
         foreach ($this->bucket as $arrayIndex => $list) {
@@ -267,7 +268,7 @@ public function containsValue($value): bool {
      */
     public function containsKey($key): bool {
         /**
-         * @var string           $arrayIndex
+         * @var string $arrayIndex
          * @var SinglyLinkedList $list
          */
         foreach ($this->bucket as $arrayIndex => $list) {
@@ -300,7 +301,7 @@ public function containsKey($key): bool {
      */
     public function getNodeByValue($value): ?Node {
         /**
-         * @var string           $arrayIndex
+         * @var string $arrayIndex
          * @var SinglyLinkedList $list
          */
         foreach ($this->bucket as $arrayIndex => $list) {

diff --git a/src/Datastructure/Stackqueue/Queue.php b/src/Datastructure/Stackqueue/Queue.php
@@ -111,7 +111,7 @@ public function rear() {
      * @return bool
      */
     public function isEmpty(): bool {
-        return $this->size() === 0;
+        return $this->tail === $this->head;
     }
 
     /**
@@ -120,7 +120,8 @@ public function isEmpty(): bool {
      * @return int
      */
     public function size(): int {
-        return $this->queueSize();
+        if ($this->tail > $this->head) return 0;
+        return $this->head - $this->tail;
     }
 
     /**

diff --git a/src/Datastructure/Stackqueue/Stack.php b/src/Datastructure/Stackqueue/Stack.php
@@ -92,7 +92,7 @@ public function sort(): void {
      * @return bool
      */
     public function isEmpty(): bool {
-        return $this->stackSize() === 0;
+        return $this->size() === 0;
     }
 
     /**