［LeetCode］Degree of an Array 数组的度 ［LeetCode］Degree of an Array 数组的度

Input: [1, 2, 2, 3, 1]
Output: 2
Explanation: 
The input array has a degree of 2 because both elements 1 and 2 appear twice.
Of the subarrays that have the same degree:
[1, 2, 2, 3, 1], [1, 2, 2, 3], [2, 2, 3, 1], [1, 2, 2], [2, 2, 3], [2, 2]
The shortest length is 2. So return 2.

Input: [1,2,2,3,1,4,2]
Output: 6

class Solution {
    public int findShortestSubArray(int[] nums) {
        Map<Integer, Integer> left = new HashMap();
        Map<Integer, Integer> right = new HashMap();
        Map<Integer, Integer> count = new HashMap();

        for(int i=0; i < nums.length; i++ ){
            if(!left.containsKey(nums[i]))
                left.put(nums[i], i);
            right.put(nums[i], i);
            count.put(nums[i], count.getOrDefault(nums[i],0)+1);
        }

        int degree = Collections.max(count.values());
        int length = Integer.MAX_VALUE;
        for(int i=0; i<nums.length; i++){
            if(count.get(nums[i])==degree){
                length = Math.min(length, right.get(nums[i]) - left.get(nums[i]) + 1);
            }
        }
        return length;
    }   
}