Leetcode longest harmonic subsequence simple

title ： The longest harmonious subsequence - Simple

subject

A harmonious array is the difference between the maximum and minimum values of elements in an array Is precisely 1 .

Now? , Give you an array of integers nums , Please find the length of the longest harmonious subsequence among all possible subsequences .

A subsequence of an array is a sequence derived from an array , It can be done by deleting some elements or not deleting elements 、 Without changing the order of the other elements .

Example 1

 Input ：nums = [1,3,2,2,5,2,3,7]
 Output ：5
 explain ： The longest harmonic subsequence is  [3,2,2,2,3]

Example 2

 Input ：nums = [1,2,3,4]
 Output ：2

Example 3

 Input ：nums = [1,1,1,1]
 Output ：0

Tips

• 1 <= nums.length <= 2 * 104
• -109 <= nums[i] <= 109

Code Java

public class FindLHS {
    
    //  Sorting solution 
    public int findLHS(int[] nums) {
    
        Arrays.sort(nums);
        int ans = 0;
        int n = nums.length;
        for (int i = 0, j = 0; j < n; j++) {
    
            while (i < j && nums[j] - nums[i] > 1) i++;
            if (nums[j] - nums[i] == 1)
                ans = Math.max(ans, j - i + 1);
        }
        return ans;
    }
    // map solve 
    public int findLHS1(int[] nums) {
    
        int ans = 0;
        Map<Integer, Integer> map = new HashMap();
        for (int i = 0; i < nums.length; i++) {
    
            map.put(nums[i], map.getOrDefault(nums[i], 0) + 1);
        }
        Set<Integer> set = map.keySet();
        for (Integer key : set) {
    
            if (map.containsKey(key + 1)) {
    
                ans = Math.max(ans, map.get(key) + map.get(key + 1));
            }
        }
        return ans;
    }

    public static void main(String[] args) {
    
        int[] nums = {
    1,3,2,2,5,2,3,7};
        System.out.println(new FindLHS().findLHS1(nums));
    }
}