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class Solution {
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  public List<String> topKFrequent(String[] words, int k) {
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    Map<String, Integer> map = new LinkedHashMap<>();
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    for (String word : words) map.put(word, map.getOrDefault(word, 0) + 1);
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    PriorityQueue<Pair<String, Integer>> queue =
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        new PriorityQueue<>(
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            new Comparator<Pair<String, Integer>>() {
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              @Override
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              public int compare(Pair<String, Integer> a, Pair<String, Integer> b) {
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                if (a.getValue() != b.getValue()) return b.getValue() - a.getValue();
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                return a.getKey().compareTo(b.getKey());
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              }
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            });
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    map.forEach(
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        (key, val) -> {
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          queue.add(new Pair(key, val));
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        });
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    List<String> list = new ArrayList<>();
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    while (k > 0) {
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      list.add(queue.poll().getKey());
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      k--;
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    }
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    return list;
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  }
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}