LeetCode 599 - Minimum Index Sum of Two Lists

https://leetcode.com/problems/minimum-index-sum-of-two-lists

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.

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).

Note:

1. The length of both lists will be in the range of [1, 1000].
2. The length of strings in both lists will be in the range of [1, 30].
3. The index is starting from 0 to the list length minus 1.
4. No duplicates in both lists.

https://www.nowtoshare.com/zh/Article/Index/70564
public String[] findRestaurant(String[] list1, String[] list2) { HashMap<String, Integer> memo = new HashMap<>(); for(int i=0;i<list1.length; i++){ memo.put(list1[i],i); } List<String> commons = new ArrayList<>(); int minIndex=Integer.MAX_VALUE; for(int i=0; i<list2.length; i++){ if(memo.containsKey(list2[i])){ int idx= memo.get(list2[i])+i; if(idx <minIndex){ commons = new ArrayList<>(); commons.add(list2[i]); minIndex =idx; } else if(idx == minIndex){ commons.add(list2[i]); } } } String[] ret = new String[commons.size()]; for(int i=0;i<ret.length;i++){ ret[i] =commons.get(i); } return ret; }

https://discuss.leetcode.com/topic/90534/java-o-n-m-time-o-n-space

public String[] findRestaurant(String[] list1, String[] list2) {
    Map<String, Integer> map = new HashMap<>();
    List<String> res = new LinkedList<>();
    int minSum = Integer.MAX_VALUE;
    for (int i=0;i<list1.length;i++) map.put(list1[i], i);
    for (int i=0;i<list2.length;i++) {
        Integer j = map.get(list2[i]);
        if (j != null && i + j <= minSum) {
            if (i + j < minSum) { res = new LinkedList<>(); minSum = i+j; }
            res.add(list2[i]);
        }
    }
    return res.toArray(new String[res.size()]);
}

https://discuss.leetcode.com/topic/90545/java-solution-hashmap-s

    public String[] findRestaurant(String[] list1, String[] list2) {
        List<String> result = null;
        Map<String, Integer> map1 = new HashMap<>();
        Map<String, Integer> map2 = new HashMap<>();
        int min = Integer.MAX_VALUE;
        
        for (int i = 0; i < list1.length; i++) {
            map1.put(list1[i], i);
        }
        for (int i = 0; i < list2.length; i++) {
            map2.put(list2[i], i);
        }
        
        for (int i = 0; i < list1.length; i++) {
            if (map2.containsKey(list1[i])) {
                int sum = map1.get(list1[i]) + map2.get(list1[i]);
                if (sum < min) {
                    min = sum;
                    result = new ArrayList<String>();
                    result.add(list1[i]);
                }
                else if (sum == min) {
                    result.add(list1[i]);
                }
            }
        }
        
        String[] res = new String[result.size()];
        for (int i = 0; i < result.size(); i++) {
            res[i] = result.get(i);
        }
        
        return res;
    }