Subarrays Distinct Element Sum of Squares II
You are given a 0-indexed integer array nums.
You are given a 0-indexed integer array nums.
The distinct count of a subarray of nums is defined as:
Return the sum of the squares of distinct counts of all subarrays of nums.
Since the answer may be very large, return it modulo 10^9 + 7.
A subarray is a contiguous non-empty sequence of elements within an array.
Example 1
Input: nums = [1,2,1]
Output: 15
Explanation: Six possible subarrays are: [1]: 1 distinct value [2]: 1 distinct value [1]: 1 distinct value [1,2]: 2 distinct values [2,1]: 2 distinct values [1,2,1]: 2 distinct values The sum of the squares of the distinct counts in all subarrays is equal to 12 + 12 + 12 + 22 + 22 + 22 = 15.
Example 2
Input: nums = [2,2]
Output: 3
Explanation: Three possible subarrays are: [2]: 1 distinct value [2]: 1 distinct value [2,2]: 1 distinct value The sum of the squares of the distinct counts in all subarrays is equal to 12 + 12 + 12 = 3.
Constraints
- 1 <= nums.length <= 10^5
- 1 <= nums[i] <= 10^5
Hints
Companies
No companies reported yet.
Discussion
Sign in to join the discussion.
Loading discussion...
Test results
No test cases yet.