palindromic_substrings.py (922B)
| # 647. Palindromic Substrings
"""
given a string 's', return the number of palindromic substrings in it. a
string is a palindrome when it reads the same backward as forward. a
substring is a contiguous sequence of charcters within the string.
"""
class Solution(object):
def countSubstrings(self, s):
"""
:type s: str
:rtype: int
"""
n, ans = len(s), 0
def palindrome_count(left, right):
cnt = 0
while left >= 0 and right < n and s[left] == s[right]:
left -= 1
right += 1
cnt += 1
return cnt
for i in range(n):
even = palindrome_count(i, i + 1)
odd = palindrome_count(i, i)
ans += even + odd
return ans
if __name__ == "__main__":
obj = Solution()
print(obj.countSubstrings("abc"))
print(obj.countSubstrings("aaa"))
|
