## 题目描述：

LeetCode 697. Degree of an Array

Given a non-empty array of non-negative integers `nums`, the degree of this array is defined as the maximum frequency of any one of its elements.

Your task is to find the smallest possible length of a (contiguous) subarray of `nums`, that has the same degree as `nums`.

Example 1:

```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.
```

Example 2:

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

Note:

• `nums.length` will be between 1 and 50,000.
• `nums[i]` will be an integer between 0 and 49,999.

O(n)遍历即可

## Python代码：

``````class Solution(object):
def findShortestSubArray(self, nums):
"""
:type nums: List[int]
:rtype: int
"""
mins = {}
maxs = {}
cnts = collections.defaultdict(int)
for idx, num in enumerate(nums):
maxs[num] = max(maxs.get(num, -1), idx)
mins[num] = min(mins.get(num, 0x7FFFFFFF), idx)
cnts[num] += 1
degree = max(cnts.values())
ans = len(nums)
for num in set(nums):
if cnts[num] == degree:
ans = min(ans, maxs[num] - mins[num] + 1)
return ans
``````

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