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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.
  • Companies:
    Mathworks, VMware, Visa

    Related Topics:
    Array

    Similar Questions:

    Solution 1.

    // OJ: https://leetcode.com/problems/degree-of-an-array/
    // Author: github.com/lzl124631x
    // Time: O(N)
    // Space: O(N)
    class Solution {
    public:
        int findShortestSubArray(vector<int>& nums) {
            unordered_map<int, int> cnt, left, right;
            int deg = 0, ans = INT_MAX;
            for (int i = 0; i < nums.size(); ++i) {
                int n = nums[i];
                cnt[n]++;
                if (cnt[n] > deg) deg = cnt[n];
                if (cnt[n] == 1) left[n] = i;
                right[n] = i;
            }
            for (auto p : cnt) {
                if (p.second != deg) continue;
                ans = min(ans, right[p.first] - left[p.first] + 1);
            }
            return ans;
        }
    };