1408.string matching in an array

class Solution {
    public List<String> stringMatching(String[] words) {
        List<String>st=new ArrayList<>();
        for(int i=0;i<words.length;i++){
            String a=words[i];
            boolean flag=true;
            for(int j=0;j<words.length;j++){
             if(j!=i){
               if(words[j].length()>=words[i].length()){
                  if(words[j].contains(words[i])){
                    flag=false;
                  }
               } 
              }
            }
            if(flag==false){
                st.add(words[i]);
            }
        }
        return st;
    }
}