Unknown error ,Plz Help

import java.util.*;
public class Main {
@SuppressWarnings(“unchecked”)
public static void main (String[] args) {
Scanner s=new Scanner(System.in);
int n=Integer.parseInt(s.next());
int k=Integer.parseInt(s.next());
String[] words=new String[n];
for(int i=0;i<n;i++){
words[i]=s.next();
}
List ans=topKFrequent(words,k);
for (String an : ans) {
System.out.print(an + " ");
}

}
public static List<String> topKFrequent(String[] words, int k) {
    List<String> ans=new ArrayList<String>();
    HashMap<String,Integer> map= new HashMap<>();

    for(String w:words){
        map.put(w,map.containsKey(w)?map.get(w)+1:1);}

    PriorityQueue[] freq =new PriorityQueue[words.length];
    for(int i=0;i<freq.length;i++){
        freq[i]=new PriorityQueue<>();
    }
    for(String w:map.keySet()){
        freq[map.get(w)-1].add(w);}

    for(int i=freq.length-1;i>=0 && k>0;i--){
        while(k>0 && !freq[i].isEmpty()){
            ans.add((String) freq[i].remove());
            k--;
        }
    }
    return ans;

}

}

Its howing this error for this code,but tis code is running fine on leetcode aswell as ide.

Note: Main.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.

@vb180198
Define the parameters for PriorityQueue

PriorityQueue<Integer> or PriorityQueue<String>

or whatever else.

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