map.ch

gistfile1.txt

# Online Python - IDE, Editor, Compiler, Interpreter

"""
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.
"""
from collections import Counter

def lengthOfLongestSubstringTwoDistinct(s):
    map = {}
    res = 0
    left = 0
    
    for i,ch in enumerate(s):
        map[ch] = map.get(ch,0)+1
        while len(map)>2:
            left_ch = s[left]
            map[left_ch] = map.get(left_ch,0)-1
            if map[left_ch]==0:
                del map[left_ch]
            
            left += 1
        res = max(res, i-left+1)
    
    return res

print(lengthOfLongestSubstringTwoDistinct("eceba"))
print(lengthOfLongestSubstringTwoDistinct("ccaabbb"))