594. Longest Harmonious Subsequence

#### QUESTION:

We define a harmonious array is 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 1:

``````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.

#### EXPLANATION:

1.获取当前key的个数count

2.与前一个对比（先判断是不是1）

3.将自己作为前一个

#### SOLUTION:

``````public class Solution {
public int findLHSHelper(int[] nums,int key,int index){
int count = 0;
for(int i = index;i<nums.length;i++){
if(nums[i]==key)
count++;
if(nums[i]!=key)
break;
}
return count;
}
public int findLHS(int[] nums) {
if (nums == null || nums.length < 2) return 0;
Arrays.sort(nums);
int index = 0;
int pre = nums[0];
Integer preCount = null;
int result = 0;
while (index < nums.length) {
int key = nums[index];
int count = findLHSHelper(nums, key, index);
index += count;

if (preCount == null || Math.abs(pre - key) > 1) {
preCount = count;
pre = key;
continue;
}

result = Math.max(result, preCount + count);
preCount = count;
pre = key;
}
return result;
}
}
``````
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