Longest Substring With At Most Two Distinct Characters

RamyHakam · RamyHakam · commit d38dbe3ab536 · 2021-11-26T17:49:41.000+01:00
diff --git a/String/LongestSubstringWithAtMostTwoDistinctCharacters.php b/String/LongestSubstringWithAtMostTwoDistinctCharacters.php
@@ -0,0 +1,34 @@
+<?php
+
+namespace Hakam\LeetCodePhp\String;
+
+class LongestSubstringWithAtMostTwoDistinctCharacters
+{
+    /**
+     * @param String $s
+     * @return Integer
+     */
+    public function lengthOfLongestSubstringTwoDistinct( string $s): int
+    {
+        if (strlen($s) <= 2) {
+            return strlen($s);
+        }
+
+        $hashList = [];
+        $left = 0;
+        $right = 0;
+        $maxLength = 0;
+
+        while ($right < strlen($s)) {
+            $hashList [$s[$right]] = $right;
+            $right++;
+            if (count($hashList) === 3) {
+                $del_index = min(array_values($hashList));
+                unset($hashList[$s[$del_index]]);
+                $left = $del_index + 1;
+            }
+            $maxLength = max($maxLength, $right - $left);
+        }
+        return $maxLength;
+    }
+}
diff --git a/Tests/Helper/InputFiles/LongestSubstringWithAtMostTwoDistinctCharactersTest.json b/Tests/Helper/InputFiles/LongestSubstringWithAtMostTwoDistinctCharactersTest.json
@@ -0,0 +1,22 @@
+{
+  "testCase1": {
+    "expectedResult": 3,
+    "input": ["eceba"]
+  },
+  "testCase2": {
+    "expectedResult": 4,
+    "input": ["abaccc"]
+  },
+  "testCase3": {
+    "expectedResult": 2,
+    "input": ["aa"]
+  },
+  "testCase4": {
+    "expectedResult": 5,
+    "input": ["ccaabbb"]
+  },
+  "testCase5": {
+    "expectedResult": 3,
+    "input": ["abee"]
+  }
+}
diff --git a/Tests/String/LongestSubstringWithAtMostTwoDistinctCharactersTest.php b/Tests/String/LongestSubstringWithAtMostTwoDistinctCharactersTest.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace Hakam\LeetCodePhp\Tests\String;
+
+use Hakam\LeetCodePhp\String\LongestSubstringWithAtMostTwoDistinctCharacters;
+use Hakam\LeetCodePhp\Tests\Helper\MainTest;
+
+/**
+ * @covers \Hakam\LeetCodePhp\String\LongestSubstringWithAtMostTwoDistinctCharacters
+ */
+class LongestSubstringWithAtMostTwoDistinctCharactersTest extends MainTest
+{
+    /**
+     * @dataProvider provideData
+     */
+    public function testWithDataList($expectedResult, $inputData): void
+    {
+        $findLongestSubString = new LongestSubstringWithAtMostTwoDistinctCharacters();
+        self::assertEquals($expectedResult,$findLongestSubString->lengthOfLongestSubstringTwoDistinct($inputData[0]));
+    }
+}
