Count Occurences of Anagrams

gfg, potd, java, medium, note

Problem Statement #

Given a word pat and a text txt. Return the count of the occurences of anagrams of the word in the text.

Note #

Check for substrings not subsequence or subset. Read Here

Solution #

class Solution {

    int search(String pat, String txt) {
        // code here
        if(pat.length()>txt.length()){
            return 0;
        }
        int a = (int)'a';
        int idx = 0;
        int pl = pat.length();
        int tl = txt.length();
        
        int[] pat_cnt = new int[26];
        int[] txt_cnt = new int[26];
        
        for(;idx<pl;idx++){
            pat_cnt[((int)pat.charAt(idx))-a]++;
            txt_cnt[((int)txt.charAt(idx))-a]++;
        }
        
        int res = 0;
        if(Arrays.equals(pat_cnt,txt_cnt)){
            res++;
        }
        
        for(;idx<tl;idx++){
            txt_cnt[((int)txt.charAt(idx-pl))-a]--;
            txt_cnt[((int)txt.charAt(idx))-a]++;
            
            if(Arrays.equals(pat_cnt,txt_cnt)){
                res++;
            }
        }
        
        return res;
    }
}