Here is my c++ solution, you can watch the explanation video here : https://youtu.be/ISg5mFFafws

vector<int> jimOrders(vector<vector<int>> orders) {
    vector<vector<int>> temp;
    for(int i = 0; i < orders.size(); i++){
        int deliver = orders[i][0] + orders[i][1];
        temp.push_back({deliver, i+1});
    }
    sort(temp.begin(), temp.end());
    vector<int> result;
    for(auto element: temp)result.push_back(element[1]);
    
    return result;
}

C#

public static List<int> jimOrders(List<List<int>> orders)
{
    var res= new List<int>();
    Dictionary<int,int> map = new Dictionary<int,int>();

    for (int i = 0; i < orders.Count;i++)
    {
        map[i+1] = orders[i][0] + orders[i][1];

    }

    var mapSort = map.OrderBy(x => x.Value).ToList();
    foreach (var item in mapSort)
    {
        res.Add(item.Key);
    }
    return res;
}

vector jimOrders(vector> orders) { vector> sum; int i = 1;

for(auto it : orders){
    int order = it[0];
    int prep = it[1];
    sum.push_back({order + prep, i});
    i++;
}
sort(sum.begin(),sum.end());

vector<int> ans;

for(auto it : sum){
    ans.push_back(it.second);
}

return ans;

}

whats wrong in this code? (2 test cases failed)

public static List jimOrders(List> orders) { // Write your code here

      List<Integer>list = new ArrayList<>();
      for(int i=0;i<orders.size();i++){
         list.add(orders.get(i).get(0)+orders.get(i).get(1)); 
       }
    List<Integer>list2 = new ArrayList<>(list);
    Collections.sort(list2);
    List<Integer>ans = new ArrayList<>();
    for(int i=0;i<list2.size();i++){
       ans.add(list.indexOf(list2.get(i))+1); 
     }
    return ans;
}

Java8

public static List<Integer> jimOrders(List<List<Integer>> orders) {
// Write your code here
List<Integer> list=new ArrayList<>();
Map<Integer,Integer> map=new HashMap<>();
int x;
for(int i=0;i<orders.size();i++){
    x=orders.get(i).get(0)+orders.get(i).get(1);
    map.put(i+1, x);
}

   //map is sorted by values
  final Map<Integer, Integer> sortedByTime = map.entrySet()
            .stream()
            .sorted(Map.Entry.comparingByValue())
            .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue, (e1, e2) -> e1, LinkedHashMap::new)); 


 for(int i : sortedByTime.keySet()){
     list.add(i);
 }

return list; }