-

Conversions/SpeedConversion.php

@@ -0,0 +1,48 @@
+<?php
+
+/**
+ * This function converts the submitted
+ * speed from one unit to another
+ *
+ * Conversion explanation taken from
+ * https://www.asknumbers.com/SpeedConversion.aspx
+ * Available units for conversion:
+ * mph -> miles per hour
+ * km/h -> kilometers per hour
+ * m/s -> meters per second
+ * ft/s -> feet per second
+ * kn -> 1 knot which is equal to 1 nautical mile (1852 km/h)
+ * The conversion is made using kilometers as base
+ *
+ * @param float $speed
+ * @param string $unitFrom
+ * @param string $unitTo
+ * @return int
+ */
+function convertSpeed(float $speed, string $unitFrom, string $unitTo)
+{
+    $speedUnitsFrom = [
+        'mph' => 1.609344,
+        'km/h' => 1,
+        'm/s'=> 3.6,
+        'ft/s'=> 1.097,
+        'kn' => 1.852,
+    ];
+    $speedUnitsTo = [
+        'mph' => 0.6213712,
+        'km/h' => 1,
+        'm/s'=> 0.277778,
+        'ft/s'=> 0.911344,
+        'kn' => 0.539957,
+    ];
+    $availableUnits = array_keys($speedUnitsFrom);
+
+    if (!is_numeric($speed)) {
+        throw new \Exception("Please pass a valid speed number for converting it from one unit to another.");
+    }
+    if (!in_array($unitFrom, $availableUnits) || !in_array($unitTo, $availableUnits)) {
+        throw new \Exception("Please pass a valid speed unit.\n\nAvailable units: " . implode(', ', $availableUnits));
+    }
+
+    return round($speed * $speedUnitsFrom[$unitFrom] * $speedUnitsTo[$unitTo], 2);
+}

DIRECTORY.md

@@ -11,6 +11,10 @@
   * [Decimaltobinary](./Conversions/DecimalToBinary.php)
   * [Hexadecimaltodecimal](./Conversions/HexadecimalToDecimal.php)
   * [Octaltodecimal](./Conversions/OctalToDecimal.php)
+  * [Speedconversion](./Conversions/SpeedConversion.php)
+
+## Graphs
+  * [Depthfirstsearch](./Graphs/DepthFirstSearch.php)
 
 ## Maths
   * [Absolutemax](./Maths/AbsoluteMax.php)
@@ -76,6 +80,8 @@
     * [Morsecodetest](./tests/Ciphers/MorseCodeTest.php)
   * Conversions
     * [Conversionstest](./tests/Conversions/ConversionsTest.php)
+  * Graphs
+    * [Depthfirstsearchtest](./tests/Graphs/DepthFirstSearchTest.php)
   * Maths
     * [Mathstest](./tests/Maths/MathsTest.php)
     * [Projecteulertest](./tests/Maths/ProjectEulerTest.php)

Graphs/DepthFirstSearch.php

@@ -0,0 +1,35 @@
+<?php
+
+/**
+ * The Depth-first Search is an algorithm used for traversing or searching trees or graphs 
+ * (https://en.wikipedia.org/wiki/Depth-first_search).
+ * 
+ * This is a non recursive implementation.
+ * 
+ * References:
+ * https://www.geeksforgeeks.org/depth-first-search-or-dfs-for-a-graph/
+ * 
+ * https://the-algorithms.com/algorithm/depth-first-search?lang=python
+ * 
+ * @author Andre Alves https://github.com/andremralves
+ * @param array $adjList An array representing the grapth as an Adjacent List
+ * @param int|string $start The starting vertex
+ * @return array The visited vertices 
+ */
+function dfs($adjList, $start)
+{
+    $visited = [];
+    $stack = [$start];
+    while (!empty($stack)) {
+        // Removes the ending element from the stack and mark as visited
+        $v = array_pop($stack);
+        $visited[$v] = 1;
+
+        // Checks each adjacent vertex of $v and add to the stack if not visited
+        foreach (array_reverse($adjList[$v]) as $adj) {
+            if (!array_key_exists($adj, $visited))
+                array_push($stack, $adj);
+        }
+    }
+    return array_keys($visited);
+}

tests/Conversions/ConversionsTest.php

@@ -9,6 +9,7 @@ require_once __DIR__ . '/../../Conversions/BinaryToDecimal.php';
 require_once __DIR__ . '/../../Conversions/DecimalToBinary.php';
 require_once __DIR__ . '/../../Conversions/OctalToDecimal.php';
 require_once __DIR__ . '/../../Conversions/HexadecimalToDecimal.php';
+require_once __DIR__ . '/../../Conversions/SpeedConversion.php';
 
 class ConversionsTest extends TestCase
 {
@@ -69,4 +70,20 @@ class ConversionsTest extends TestCase
         $this->expectExceptionMessage('Please pass a valid Hexadecimal Number for Converting it to a Decimal Number.');
         hexToDecimal("this is a string");
     }
+
+    public function testSpeedConversion()
+    {
+        assertEquals(convertSpeed(5, 'm/s', 'mph'), 11.18);
+        assertEquals(convertSpeed(5, 'ft/s', 'km/h'), 5.49);
+        assertEquals(convertSpeed(3, 'km/h', 'km/h'), 3);
+        assertEquals(convertSpeed(7, 'kn', 'km/h'), 12.96);
+        assertEquals(convertSpeed(12, 'mph', 'km/h'), 19.31);
+        assertEquals(convertSpeed(0.514, 'm/s', 'kn'), 1);
+
+        $this->expectException(\Exception::class);
+        convertSpeed('1', 'km/h', 'mph');
+
+        $this->expectException(\Exception::class);
+        convertSpeed(1, 'km/h', 'miles');
+    }
 }

tests/Graphs/DepthFirstSearchTest.php

@@ -0,0 +1,48 @@
+<?php
+
+require_once __DIR__ . '/../../vendor/autoload.php';
+require_once __DIR__ . '/../../Graphs/DepthFirstSearch.php';
+
+use PHPUnit\Framework\TestCase;
+
+class DepthFirstSearchTest extends TestCase
+{
+    public function testDepthFirstSearch()
+    {
+        $graph = array(
+            "A" => ["B", "C", "D"],
+            "B" => ["A", "D", "E"],
+            "C" => ["A", "F"],
+            "D" => ["B", "D"],
+            "E" => ["B", "F"],
+            "F" => ["C", "E", "G"],
+            "G" => ["F"],
+        );
+        $visited = dfs($graph, "A");
+        $this->assertEquals(["A", "B", "D", "E", "F", "C", "G"], $visited);
+    }
+    public function testDepthFirstSearch2()
+    {
+        $graph = array(
+            [1, 2],
+            [2],
+            [0, 3],
+            [3],
+        );
+
+        $visited = dfs($graph, 2);
+        $this->assertEquals([2, 0, 1, 3], $visited);
+    }
+    public function testDepthFirstSearch3()
+    {
+        $graph = array(
+            [2, 3, 1],
+            [0],
+            [0, 4],
+            [0],
+            [2],
+        );
+        $visited = dfs($graph, 0);
+        $this->assertEquals([0, 2, 4, 3, 1], $visited);
+    }
+}