Optimize Duplicate Pair Detection | Dataford Interview Questions

At Stripe, an existing utility scans a list of integers with nested loops to find values that appear more than once. Rewrite it for better performance.

Implement a function find_duplicates(nums) that returns all distinct duplicate values in ascending order, along with how many times each value appears.

Formal Specification

Input: nums, a list of integers
Output: a list of lists, where each element is [value, count] for every integer that appears at least twice
The result must be sorted by value in ascending order

Constraints

0 <= len(nums) <= 10^5
-10^9 <= nums[i] <= 10^9
Return each duplicated value once with its total frequency
Output must be sorted by value in ascending order

Function Signature

def find_duplicates(nums):

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