leetcode 599. Minimum Index Sum of Two Lists

1.题目

Suppose Andy and Doris want to choose a restaurant for dinner, and they both have a list of favorite restaurants represented by strings.

You need to help them find out their common interest with the least list index sum. If there is a choice tie between answers, output all of them with no order requirement. You could assume there always exists an answer.
有两个包含餐馆名的数组，求他们共有的最小下标和的餐馆名称。
Example 1:

Input:
[“Shogun”, “Tapioca Express”, “Burger King”, “KFC”]
[“Piatti”, “The Grill at Torrey Pines”, “Hungry Hunter Steakhouse”, “Shogun”]
Output: [“Shogun”]
Explanation: The only restaurant they both like is “Shogun”.

Example 2:

Input:
[“Shogun”, “Tapioca Express”, “Burger King”, “KFC”]
[“KFC”, “Shogun”, “Burger King”]
Output: [“Shogun”]
Explanation: The restaurant they both like and have the least index sum is “Shogun” with index sum 1 (0+1).

2.分析

两个数组都需要遍历一遍。
遍历第一个数组，用哈希表或字典或map记录元素值对应下标。
遍历第二个数组，相同元素的下标值相加，找出最小的。

3.代码

class Solution(object):
    def findRestaurant(self, list1, list2):
        pos1={v:pos for pos,v in enumerate(list1)}
        length=len(list2)+len(list1)
        result=[]
        mind=length
        for i,v in enumerate(list2):
            j=pos1.get(v,length)
            if i+j < mind:#更新最小值
                result=[v]
                mind=i+j
            elif i+j==mind:#最小值一样
                result.append(v)
        return result