Added code for findng no of homogenous substrings (#146)

* Create CountHomogenous.php

Added count no of homogenous substrings

* Added program for finding no. of homogenous substrings

* Update Strings/CountHomogenous.php

Co-authored-by: Brandon Johnson <bbj1979@gmail.com>

* Update Strings/CountHomogenous.php

Co-authored-by: Brandon Johnson <bbj1979@gmail.com>

* Update tests/Strings/StringsTest.php

Co-authored-by: Brandon Johnson <bbj1979@gmail.com>

* Update StringsTest.php

* Update Strings/CountHomogenous.php

Co-authored-by: Brandon Johnson <bbj1979@gmail.com>

* Update tests/Strings/StringsTest.php

Co-authored-by: Brandon Johnson <bbj1979@gmail.com>

* Update CountHomogenous.php

* Update tests/Strings/StringsTest.php

* Update tests/Strings/StringsTest.php

* Fix homogenous count unit test

* Fix count homogenous substrings algorithm

* PHPCBF: remove inline control structure

---------

Co-authored-by: Brandon Johnson <bbj1979@gmail.com>

DIRECTORY.md

@@ -87,6 +87,7 @@
   * [Checkpalindrome](./Strings/CheckPalindrome.php)
   * [Checkpalindrome2](./Strings/CheckPalindrome2.php)
   * [Countconsonants](./Strings/CountConsonants.php)
+  * [Counthomogenous](./Strings/CountHomogenous.php)
   * [Countsentences](./Strings/CountSentences.php)
   * [Countvowels](./Strings/CountVowels.php)
   * [Distance](./Strings/Distance.php)

Strings/CountHomogenous.php

@@ -0,0 +1,32 @@
+<?php
+
+/**
+ * Count homogenous substrings
+ * @param String $s
+ * @return Integer
+ */
+function countHomogenous($s)
+{
+    // Initialize the count of homogeneous substrings
+    $count = 0;
+
+    // Length of the string
+    $length = strlen($s);
+
+    if ($length == 0) {
+        return 0; // If the string is empty, return 0
+    }
+
+    // Initialize the count of homogeneous substrings
+    $count = 1; // Start with 1 since the first character itself starts a substring
+
+    // Loop through each character in the string, starting from the second character
+    for ($i = 1; $i < $length; $i++) {
+        // Check if current character is not the same as the previous one
+        if ($s[$i] != $s[$i - 1]) {
+            $count++; // A new substring starts, increment the count
+        }
+    }
+
+    return $count;
+}

tests/Strings/StringsTest.php

@@ -8,6 +8,7 @@ require_once __DIR__ . '/../../Strings/CheckAnagram.php';
 require_once __DIR__ . '/../../Strings/CheckPalindrome.php';
 require_once __DIR__ . '/../../Strings/CheckPalindrome2.php';
 require_once __DIR__ . '/../../Strings/CountConsonants.php';
+require_once __DIR__ . '/../../Strings/CountHomogenous.php';
 require_once __DIR__ . '/../../Strings/CountSentences.php';
 require_once __DIR__ . '/../../Strings/CountVowels.php';
 require_once __DIR__ . '/../../Strings/Distance.php';
@@ -81,6 +82,11 @@ class StringsTest extends TestCase
         $this->assertEquals(7, countConsonants("hello world"));
         $this->assertEquals(9, countConsonants("Just A list of somE aaaaaaaaaa"));
     }
+    public function testCountHomogenous()
+    {
+        $this->assertEquals(4, countHomogenous("abbcccaa"));
+        $this->assertEquals(2, countHomogenous("xy"));
+    }
 
     public function testFindDistance()
     {