initial commit

.gitignore

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+.idea/
+
+/vendor/
+
+composer.lock

composer.json

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+{
+  "name": "doganoo/php-algorithms",
+  "description": "A collection of common algorithms implemented in PHP. The collection is based on \"Cracking the Coding Interview\" by Gayle Laakmann McDowell",
+  "type": "library",
+  "license": "MIT",
+  "authors": [
+    {
+      "name": "Dogan Ucar",
+      "email": "dogan@dogan-ucar.de"
+    }
+  ],
+  "autoload": {
+    "psr-4": {
+      "doganoo\\PHPAlgorithms\\": "src/"
+    }
+  },
+  "minimum-stability": "stable",
+  "require-dev": {
+    "phpunit/phpunit": "6.5"
+  }
+}

phpunit.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit backupGlobals="false"
+         backupStaticAttributes="false"
+         bootstrap="vendor/autoload.php"
+         colors="true"
+         convertErrorsToExceptions="true"
+         convertNoticesToExceptions="true"
+         convertWarningsToExceptions="true"
+         processIsolation="false"
+         stopOnFailure="false"
+         syntaxCheck="false">
+    <testsuites>
+        <testsuite name="PHPAlgorithms Test Suite">
+            <directory suffix=".php">./tests/</directory>
+        </testsuite>
+    </testsuites>
+</phpunit>

src/Graph/Graph.php

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+<?php
+/**
+ * MIT License
+ *
+ * Copyright (c) 2018 Dogan Ucar
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+namespace doganoo\PHPAlgorithms\Graph;
+
+class Graph
+{
+    private $nodes = [];
+
+    private function getNode($id)
+    {
+        if (array_key_exists($id, $this->nodes)) {
+            return $this->nodes[$id];
+        }
+        return null;
+    }
+
+    public function addEdge(int $source, int $destination)
+    {
+        $sourceNode = $this->getNode($source);
+        if ($sourceNode == null) {
+            $sourceNode = new Node($source);
+        }
+        $destinationNode = $this->getNode($destination);
+        if ($destinationNode == null) {
+            $destinationNode = new Node($destination);
+        }
+        $sourceNode->addAdjacent($destinationNode);
+        $this->nodes[$source] = $sourceNode;
+//        $destinationNode->addAdjacent($sourceNode);
+        $this->nodes[$destination] = $destinationNode;
+    }
+
+    public function hasDfs(int $source, int $destination)
+    {
+        $sourceNode = $this->getNode($source);
+        $destinationNode = $this->getNode($destination);
+        if ($destinationNode == null) {
+            $destinationNode = new Node($destination);
+        }
+        if ($sourceNode === null) {
+            return false;
+        }
+        return $this->hasDfsInternal($sourceNode, $destinationNode, []);
+    }
+
+    private function hasDfsInternal(Node $source, Node $destination, array $visited)
+    {
+        if (in_array($source->getValue(), $visited)) {
+            return false;
+        }
+        $visited[] = $source->getValue();
+        if ($source->getValue() == $destination->getValue()) {
+            return true;
+        }
+
+        /** @var Node $adjacent */
+        foreach ($source->getAdjacents() as $adjacent) {
+            if ($this->hasDfsInternal($adjacent, $destination, $visited)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    public function hasBfs(int $s, int $d)
+    {
+        $source = $this->getNode($s);
+        $destination = $this->getNode($d);
+        $nextToVisit = [];
+        $visited = [];
+
+        $nextToVisit[] = $source;
+
+        while (count($nextToVisit) !== 0) {
+            reset($nextToVisit);
+            $key = key($nextToVisit);
+            $node = $nextToVisit[$key];
+            unset($nextToVisit[$key]);
+
+            if ($node == null) {
+                return false;
+            }
+            if ($destination == null) {
+                return false;
+            }
+            if ($node->getValue() == $destination->getValue()) {
+                return true;
+            }
+            if (in_array($node->getValue(), $visited)) {
+                return false;
+            }
+            $visited[] = $node->getValue();
+
+            foreach ($node->getAdjacents() as $child) {
+                $nextToVisit[] = $child;
+            }
+        }
+        return false;
+    }
+
+
+}

src/Graph/Node.php

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+<?php
+/**
+ * MIT License
+ *
+ * Copyright (c) 2018 Dogan Ucar
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+namespace doganoo\PHPAlgorithms\Graph;
+class Node
+{
+    private $value = 0;
+    private $adjacent = [];
+
+    public function __construct(int $value)
+    {
+        $this->value = $value;
+    }
+
+    public function addAdjacent(Node $node)
+    {
+        $this->adjacent[] = $node;
+    }
+
+    public function getValue()
+    {
+        return $this->value;
+    }
+
+    public function getAdjacents()
+    {
+        return $this->adjacent;
+    }
+
+    public function __toString()
+    {
+        return "" . $this->value;
+    }
+}

src/LinkedLists/Addition.php

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+<?php
+/**
+ * MIT License
+ *
+ * Copyright (c) 2018 Dogan Ucar
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+namespace doganoo\PHPAlgorithms\LinkedLists;
+
+
+class Addition
+{
+    public function addLists(?Node $node1, ?Node $node2, int $carry = 0)
+    {
+        if ($node1 == null || $node2 == null) {
+            return null;
+        }
+        $resultNode = new Node();
+
+        $value = $carry;
+
+        $value += $node1->getValue();
+        $value += $node2->getValue();
+
+        $resultNode->setValue($value % 10);
+
+        $more = $this->addLists($node1->getNext(), $node2->getNext(), $value > 10 ? 1 : 0);
+        $resultNode->setNext($more);
+
+        return $resultNode;
+    }
+
+}