import java.util.*;

class Solution {
    public List<Integer> findStringAnagrams(String str, String pattern) {
      List<Integer> resultIndices = new ArrayList<Integer>();

      Map<Character, Integer> patternMap = new HashMap<>();
      for(Character c: pattern.toCharArray()) {
        patternMap.put(c, patternMap.getOrDefault(c, 0)+1);
      }

      char[] arr = str.toCharArray();
      int n = arr.length, plen = pattern.length();
      Map<Character, Integer> map = new HashMap<>();
      for(int i = 0; i < plen; i ++) {
        map.put(arr[i], map.getOrDefault(arr[i], 0)+1);
      }

      if(isMatch(map, patternMap)) {
        resultIndices.add(0);
      }

      int st = 0;
      for(int end = plen; end < n; end++) {
        map.put(arr[end], map.getOrDefault(arr[end], 0)+1);
        map.put(arr[st], map.get(arr[st]) - 1);
        if(map.get(arr[st]) == 0) {
          map.remove(arr[st]);
        }
        st++;
        if(isMatch(map, patternMap)) {
          resultIndices.add(st);
        }
      }
      
      return resultIndices;
  }

  public boolean isMatch(Map<Character, Integer> m1, Map<Character, Integer> m2) {
    if(m1.isEmpty() || m2.isEmpty()) return false;
    if(m1.size() != m2.size())
      return false;

    for(Character c: m1.keySet()) {
      if(m1.get(c) != m2.get(c)) 
        return false;
    }

    return true;
  }
}