Minimum Index Sum of Two Lists Python Solution

lcpy gen -n 599   # by problem number
lcpy gen -s minimum_index_sum_of_two_lists   # by problem name

Input: list1 = ["Shogun","Tapioca Express","Burger King","KFC"], list2 = ["Piatti","The Grill at Torrey Pines","Hungry Hunter Steakhouse","Shogun"]
Output: ["Shogun"]
Explanation: The only common string is "Shogun".

Input: list1 = ["Shogun","Tapioca Express","Burger King","KFC"], list2 = ["KFC","Shogun","Burger King"]
Output: ["Shogun"]
Explanation: The common string with the least index sum is "Shogun" with index sum = (0 + 1) = 1.

Input: list1 = ["happy","sad","good"], list2 = ["sad","happy","good"]
Output: ["sad","happy"]
Explanation: There are three common strings:
"happy" with index sum = (0 + 1) = 1.
"sad" with index sum = (1 + 0) = 1.
"good" with index sum = (2 + 2) = 4.
The strings with the least index sum are "sad" and "happy".

class Solution:
    # Time: O(n + m)
    # Space: O(m)
    def find_restaurant(self, list1: list[str], list2: list[str]) -> list[str]:
        index_in_list2 = {s: i for i, s in enumerate(list2)}
        best_sum = len(list1) + len(list2)
        result: list[str] = []
        for i, s in enumerate(list1):
            j = index_in_list2.get(s)
            if j is None:
                continue
            total = i + j
            if total < best_sum:
                best_sum = total
                result = [s]
            elif total == best_sum:
                result.append(s)
        return result