MinimumIndexSumOfTwoList.java

  /*
  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".
*/

class Solution {
     public String[] findRestaurant(String[] list1, String[] list2) {
        List<String> words = new ArrayList<>();
        int minSum = 5000;
       
        for(int i = 0; i < list1.length; i++){
            int matchIndex = Arrays.asList(list2).indexOf(list1[i]);
            
            if( matchIndex >= 0 && matchIndex + i < minSum){
                minSum = matchIndex + i;
                words.clear();
                
                words.add(list1[i]);
                continue;
            } else if( matchIndex >= 0 && (matchIndex + i) == minSum ){
                words.add(list1[i]);
            }
        }

        return words.toArray(new String[words.size()]);
    }
}