Find Second Largest in Array

Problem

Given an array of integers nums, return the second largest distinct number in the array. If the array does not contain at least two distinct values, return None. The input is an unsorted list, and the solution should work efficiently without requiring a full sort.

Constraints

• 1 <= len(nums) <= 10^5
• -10^9 <= nums[i] <= 10^9
• Return None if fewer than two distinct values exist
• The array may contain duplicate values