feat(leetcode): add No.3090

Author: mickey0524

3090.Maximum-Length-Substring-With-Two-Occurrences.java

@@ -0,0 +1,32 @@
+// https://leetcode.com/problems/maximum-length-substring-with-two-occurrences/description/
+// algorithms
+// Easy (62.2%)
+// Total Accepted: 25.6K
+// Total Submissions: 41.1K
+
+
+class Solution {
+
+    public int maximumLengthSubstring(String s) {
+        int[] nums = new int[26];
+        int sLen = s.length();
+        int beforeIdx = 0;
+        int res = 0;
+
+        for (int i = 0; i < sLen; i++) {
+            char ch = s.charAt(i);
+            int chIdx = ch - 'a';
+            nums[chIdx] += 1;
+
+            while (beforeIdx < i && nums[chIdx] > 2) {
+                nums[s.charAt(beforeIdx) - 'a'] -= 1;
+                beforeIdx += 1;
+            }
+            
+            res = Math.max(res, i - beforeIdx + 1);
+        }
+        
+        return res;
+    }
+
+}