BinarySearch 0463 Count of Sublists with Same First and Last Values

Problem statement

https://binarysearch.com/problems/Count-of-Sublists-with-Same-First-and-Last-Values/

Solution

For each value x if we have t places, we can get t * (t + 1)//2 segments.

Complexity

It is O(n) for time and space.

Code

class Solution:
    def solve(self, nums):
        return sum(x*(x+1)//2 for x in Counter(nums).values())