solves #3090: Maximum Length Substring With Two Occurrences in java

Author: anishLearnsToCode

Diff for: README.md

@@ -899,7 +899,7 @@
 | 3074 | [Apple Redistribution into Boxes](https://leetcode.com/problems/apple-redistribution-into-boxes)                                                                       |                                                                                [![Java](assets/java.png)](src/AppleRedistributionIntoBoxes.java)                                                                                 |                                                                                                                                   |
 | 3079 | [Find the Sum of Encrypted Integers](https://leetcode.com/problems/find-the-sum-of-encrypted-integers)                                                                 |                                                                                [![Java](assets/java.png)](src/FindTheSumOfEncryptedIntegers.java)                                                                                |                                                                                                                                   |
 | 3083 | [Existence of a Substring in a String and Its Reverse](https://leetcode.com/problems/existence-of-a-substring-in-a-string-and-its-reverse)                             |                                                                         [![Java](assets/java.png)](src/ExistenceOfASubstringInAStringAndItsReverse.java)                                                                         |                                                                                                                                   |
-| 3090 | [Maximum Length Substring With Two Occurrences](https://leetcode.com/problems/maximum-length-substring-with-two-occurrences)                                           |                                                                                                                                                                                                                                  |                                                                                                                                   |
+| 3090 | [Maximum Length Substring With Two Occurrences](https://leetcode.com/problems/maximum-length-substring-with-two-occurrences)                                           |                                                                          [![Java](assets/java.png)](src/MaximumLengthSubstringWithTwoOccurrences.java)                                                                           |                                                                                                                                   |
 | 3095 | [Shortest Subarray With OR at Least K I](https://leetcode.com/problems/shortest-subarray-with-or-at-least-k-i)                                                         |                                                                                                                                                                                                                                  |                                                                                                                                   |
 | 3099 | [Harshad Number](https://leetcode.com/problems/harshad-number)                                                                                                         |                                                                                                                                                                                                                                  |                                                                                                                                   |
 | 3105 | [Longest Strictly Increasing or Strictly Decreasing Subarray](https://leetcode.com/problems/longest-strictly-increasing-or-strictly-decreasing-subarray)               |                                                                                                                                                                                                                                  |                                                                                                                                   |

Diff for: src/MaximumLengthSubstringWithTwoOccurrences.java

@@ -0,0 +1,26 @@
+// https://leetcode.com/problems/maximum-length-substring-with-two-occurrences
+// T: O(N)
+// S: O(1)
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class MaximumLengthSubstringWithTwoOccurrences {
+    public int maximumLengthSubstring(String s) {
+        final Map<Character, Integer> frequencies = new HashMap<>();
+        int maxLength = 1;
+
+        for (int left = 0, right = 0 ; left < s.length() && right < s.length() ; ) {
+            if (frequencies.getOrDefault(s.charAt(right), 0) == 2) {
+                frequencies.put(s.charAt(left), frequencies.get(s.charAt(left)) - 1);
+                left++;
+            } else {
+                frequencies.put(s.charAt(right), frequencies.getOrDefault(s.charAt(right), 0) + 1);
+                right++;
+                maxLength = Math.max(maxLength, right - left);
+            }
+        }
+
+        return maxLength;
+    }
+}