Longest Substring Without Repeating Characters

src/main/java/String/LongestSubstringWithoutRepeatingCharacters.java

@@ -0,0 +1,20 @@
+package String;
+public class LongestSubstringWithoutRepeatingCharacters {
+    public int lengthOfLongestSubstring(String s) {
+        int pointer = 0;
+        int max = 0;
+        StringBuilder sBuilder = new StringBuilder();
+        while (pointer < s.length()) {
+            char c = s.charAt(pointer);
+            int index = sBuilder.indexOf(String.valueOf(c));
+            if (index >= 0) {
+                sBuilder.delete(0, index + 1);
+            }
+            sBuilder.append(c);
+            max = Math.max(max, sBuilder.length());
+            pointer++;
+        }
+        return max;
+
+    }
+}

src/test/java/TestLongestSubstringWithoutRepeatingCharacters.java

@@ -0,0 +1,52 @@
+import String.LongestSubstringWithoutRepeatingCharacters;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+public class TestLongestSubstringWithoutRepeatingCharacters {
+
+    private LongestSubstringWithoutRepeatingCharacters repeatingCharacters;
+
+    @Before
+    public void setUp(){
+        repeatingCharacters = new LongestSubstringWithoutRepeatingCharacters();
+    }
+
+    @Test
+    public void testCase1()
+    {
+        String  s = "abcabcbb";
+        int expectedoutput = 3;
+        Assert.assertEquals(expectedoutput,repeatingCharacters.lengthOfLongestSubstring(s));
+    }
+    @Test
+    public void testCase2()
+    {
+        String  s = "bbbbb";
+        int expectedoutput = 1;
+        Assert.assertEquals(expectedoutput,repeatingCharacters.lengthOfLongestSubstring(s));
+    }
+    @Test
+    public void testCase3()
+    {
+        String  s = "pwwkew";
+        int expectedoutput = 3;
+        Assert.assertEquals(expectedoutput,repeatingCharacters.lengthOfLongestSubstring(s));
+    }
+    //aab
+    @Test
+    public void testCase4()
+    {
+        String  s = "aab";
+        int expectedoutput = 2;
+        Assert.assertEquals(expectedoutput,repeatingCharacters.lengthOfLongestSubstring(s));
+    }
+    //dvdf
+    @Test
+    public void testCase5()
+    {
+        String  s = "dvdf";
+        int expectedoutput = 3;
+        Assert.assertEquals(expectedoutput,repeatingCharacters.lengthOfLongestSubstring(s));
+    }
+}