Longest Substring with At Most Two Distinct Characters
# Given a string, find the length of the longest substring T that contains at most 2 distinct characters.
# For example, Given s = “eceba”,
# T is "ece" which its length is 3.
# Hide Company Tags Google
# Hide Tags Hash Table Two Pointers String
# Hide Similar Problems (M) Longest Substring Without Repeating Characters (H) Sliding Window Maximum (H) Longest Substring with At Most K Distinct Characters
class Solution(object):
def lengthOfLongestSubstringTwoDistinct(self, s):
"""
:type s: str
:rtype: int
"""
char1, right1, char2, right2 = '', 0, '', 0
start = 0
longest = 0
for i, c in enumerate(s):
if not char1 or char1==c:
char1=c
right1=i
elif not char2 or char2==c:
char2=c
right2=i
else:
# print i
if right1<right2:
char1 = c
start=right1+1
right1 = i
else:
char2 = c
start=right2+1
right2 = i
#print 'i={},start={},right1={},righ2={}'.format(i,start,right1,right2)
longest = max(longest, i-start+1)
return longest
sol = Solution()
assert sol.lengthOfLongestSubstringTwoDistinct("cdaba")==3
