## DEV Community

Abhishek Chaudhary

Posted on

# Find All Anagrams in a String

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.

An Anagram is a word or phrase formed by rearranging the letters of a different word or phrase, typically using all the original letters exactly once.

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` and `p` consist of lowercase English letters.

SOLUTION:

``````class Solution:
def findAnagrams(self, s: str, p: str) -> List[int]:
np = len(p)
ns = len(s)
op = []
if np > ns:
return op
pctr = [0] * 26
for c in p:
pctr[ord(c) - ord('a')] += 1
sctr = [0] * 26
for i in range(np):
sctr[ord(s[i]) - ord('a')] += 1
i = 0
while i < ns - np:
if pctr == sctr:
op.append(i)
sctr[ord(s[i]) - ord('a')] -= 1
sctr[ord(s[i + np]) - ord('a')] += 1
i += 1
if pctr == sctr:
op.append(i)
return op
``````