599. Minimum Index Sum of Two Lists

Easy

Given two arrays of strings list1 and list2, find the common strings with the least index sum.

A common string is a string that appeared in both list1 and list2.

A common string with the least index sum is a common string such that if it appeared at list1[i] and list2[j] then i + j should be the minimum value among all the other common strings.

Return all the common strings with the least index sum. Return the answer in any order.

Example 1:

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".

Example 2:

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.

Example 3:

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".

Constraints:

• 1 <= list1.length, list2.length <= 1000

• 1 <= list1[i].length, list2[i].length <= 30

• list1[i] and list2[i] consist of spaces ' ' and English letters.

• All the strings of list1 are unique.

• All the strings of list2 are unique.

• There is at least a common string between list1 and list2.

解題

func findRestaurant(list1 []string, list2 []string) []string {
    m := make(map[string]int)

    for i, s := range list1 {
        m[s] = i
    }

    arr := make([][]string, len(list1) + len(list2) + 1)
    ans := 20000
    for i, s := range list2 {
        if v, ok := m[s]; ok {
            arr[i + v] = append(arr[i + v], s)
            ans = min(ans, i + v)
        }
    }
    if ans == 20000 { return []string{} }
    return arr[ans]
}

func min(a, b int) int {
    if a < b { return a }
    return b
}