Leetcode - Find All Anagrams in a String Solution
Given two strings s
and p
, return an array of all the start indices of p
's anagrams in s
. You may return the answer in any order.
Example 1:
Input: s = "cbaebabacd", p = "abc"
Output: [0,6]
Explanation:
The substring with start index = 0 is "cba", which is an anagram of "abc".
The substring with start index = 6 is "bac", which is an anagram of "abc".
Example 2:
Input: s = "abab", p = "ab"
Output: [0,1,2]
Explanation:
The substring with start index = 0 is "ab", which is an anagram of "ab".
The substring with start index = 1 is "ba", which is an anagram of "ab".
The substring with start index = 2 is "ab", which is an anagram of "ab".
Constraints:
1 <= s.length, p.length <= 3 * 104
s
andp
consist of lowercase English letters.
Solution in Python
class Solution:
def findAnagrams(self, s: str, p: str) -> List[int]:
start = 0
stop = len(p)-1
found = []
count_s = Counter(s[start:stop])
count_p = Counter(p)
for i in range(stop,len(s)):
first_letter = s[i-stop]
last_letter = s[i]
count_s[last_letter]+=1
if count_s == count_p:
found.append(i-stop)
if count_s[first_letter] == 1:
del count_s[first_letter]
else:
count_s[first_letter] -= 1
return found