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 * 10<sup>4</sup>

• s and p consist of lowercase English letters.

Solution:

Language: Java

class Solution 
{
    public List<Integer> findAnagrams(String s, String p) 
    {
      List<Integer> res = new ArrayList<>();
        if (p.length() > s.length()) 
        {
            return Collections.emptyList();
        }

        for (int i = 0; i < s.length()-p.length()+1; i++) 
        {
            if (checkArray(s.substring(i, i + p.length()), p)) 
            {
                res.add(i);
            }
        }
        return res; 
    }

     public static boolean checkArray(String s, String t) 
     {
        int[] chars = new int[26];

        for (char current : s.toCharArray()) 
        {
            int z = current - 'a';
            chars[z]++;
        }

        for (char current : t.toCharArray()) 
        {
            chars[current - 'a']--;
        }

        for (int current : chars) 
        {
            if (current != 0) 
            {
                return false;
            }
        }
        return true;
    }
}