Leetcode 3rd problem LengthOfLongest substring

Author: Codes-Lab

LengthOfLongestSubstring.java

@@ -0,0 +1,70 @@
+import java.util.List;
+import java.util.Set;
+import java.util.ArrayList;
+import java.util.HashSet;
+
+/**
+Given a string s, find the length of the longest 
+substring without repeating characters.
+ 
+Example 1:
+Input: s = "abcabcbb"
+Output: 3
+Explanation: The answer is "abc", with the length of 3.
+Example 2:
+
+Input: s = "bbbbb"
+Output: 1
+Explanation: The answer is "b", with the length of 1.
+Example 3:
+
+Input: s = "pwwkew"
+Output: 3
+Explanation: The answer is "wke", with the length of 3.
+Notice that the answer must be a substring, "pwke" is a subsequence and not a substring.
+ 
+
+Constraints:
+
+0 <= s.length <= 5 * 104
+s consists of English letters, digits, symbols and spaces.
+ */
+public class LengthOfLongestSubstring {
+    public static void main(String[] args) {
+        String s1 = "abcabcbb";
+        String s2 = "pwwkew"; 
+        String s3 = "au"; 
+        String s4 = "dvdf";
+        String s5 = " ";
+        String s6 = "bpfbhmipx";
+        int longestString = lengthOfLongestSubstring(s6);
+        System.out.println(longestString);
+    }
+    public static int lengthOfLongestSubstring(String s) {
+        int stringLen = 0;
+        String chars = new String();
+    
+        for (int index = 0; index < s.length(); index++) {
+            char c = s.charAt(index);
+            if(chars.contains(String.valueOf(c))) {
+                String newChars = new String();
+                for (int i=chars.length() - 1; i >=0; i--) {
+                    char pchar = chars.charAt(i);
+                    if(pchar != c) {
+                        newChars = String.valueOf(pchar) + newChars;
+                    } else {
+                        chars = newChars;
+                        break;
+                    }
+                }
+                chars = chars + String.valueOf(c);
+            } else {
+                chars = chars + String.valueOf(c);
+            }
+            if(stringLen < chars.length()) {
+                stringLen = chars.length();
+            }
+        }
+        return stringLen;
+    }
+}