Longest Substring with At Most Two Distinct Characters

Author: saurabhchris1

Longest_Substring_with_At_Most_Two_Distinct_Characters.py

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+# Given a string s , find the length of the longest substring t  that contains at most 2 distinct characters.
+#
+# Example 1:
+#
+# Input: "eceba"
+# Output: 3
+# Explanation: t is "ece" which its length is 3.
+# Example 2:
+#
+# Input: "ccaabbb"
+# Output: 5
+# Explanation: t is "aabbb" which its length is 5.
+
+
+class Solution:
+    def lengthOfLongestSubstringTwoDistinct(self, s):
+        last_char = ''
+        second_last_char = ''
+        last_char_count = 0
+        maximum = 0
+        currentMax = 0
+
+        for char in s:
+            if char == last_char or char == second_last_char:
+                currentMax += 1
+            else:
+                currentMax = last_char_count + 1
+
+            if char == last_char:
+                last_char_count += 1
+            else:
+                last_char_count = 1
+                second_last_char = last_char
+                last_char = char
+
+            maximum = max(currentMax, maximum)
+
+        return maximum