[LeetCode] Problem 594 - Longest Harmonious Subsequence

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We define a harmounious array as an array where the difference between its maximum value and its minimum value is exactly 1.

Now, given an integer array, you need to find the length of its longest harmonious subsequence among all its possible subsequences.

Example

Input: [1,3,2,2,5,2,3,7]

Output: 5

Explanation: The longest harmonious subsequence is [3,2,2,2,3].

Note

The length of the input array will not exceed 20,000.

Code

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public int findLHS(int[] nums) {
    int result = 0;
    Map<Integer, Integer> map = new HashMap<>();

    for (int num : nums)
        map.put(num, map.getOrDefault(num, 0) + 1);

    for (Map.Entry<Integer, Integer> entry : map.entrySet()) {
        int key = entry.getKey();

        if (map.containsKey(key + 1))
            result = Math.max(result, entry.getValue() + map.get(key + 1));
    }

    return result;
}