Question
Given a list of strings, write a function to get the kth most frequently occurring string.
eg.
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kthMostFrequent({"a","b","c","a","b","a"}, 0) = "a" kthMostFrequent({"a","b","c","a","b","a"}, 1) = "b" kthMostFrequent({"a","b","c","a","b","a"}, 2) = "c" kthMostFrequent({"a","b","c","a","b","a"}, 3) = null |
Once you think that you’ve solved the problem, click below to see the solution.
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Solution
How was that problem? You can check out the solution in the video below.
Here is the source code for the solution shown in the video:
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public String kthMostFrequent(String[] strings, int k) { HashMap<String, Integer> map = new HashMap<String, Integer>(); for (String s : strings) { Integer x = map.get(s); if (x == null) x = 0; map.put(s, ++x); } List list = new ArrayList(map.entrySet()); Collection.sort(list, new Comparator() { public int compare(Object o1, Object o2) { Integer v1 = (Integer) ((Map.Entry) o1).getValue(); Integer v2 = (Integer) ((Map.Entry) o2).getValue(); return v1.compareTo(v2); } }); if (list.size() > k) return (String) (list.get(k)).getKey(); return null; } |
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