This information is really helpfull for thoese who are interested in custom ecommerce development

public static List closestNumbers(List arr) { // Write your code here

    // 5,4,3,2
    List<List<Integer>> list = new ArrayList<>(arr.size() - 1);
    for (int i = 0; i < arr.size() - 1; i++) {
        list.add(new ArrayList<>());
    }
    arr = arr.stream().sorted().collect(Collectors.toList());

    for (int i = 0; i < arr.size() - 1; i++) {
        list.get(i).add(arr.get(i));
        list.get(i).add(arr.get(i + 1));
    }

    List<Integer> ind = new ArrayList<>();

    for (int i = 0; i < list.size(); i++) {
        ind.add(list.get(i).get(1) - list.get(i).get(0));
    }

    int smaller = ind.stream().min(Comparator.naturalOrder()).orElse(0);

    List<Integer> res = new ArrayList<>();
    for (int i = 0; i < ind.size(); i++) {
        if (ind.get(i) == smaller) {
            list.get(i).forEach(f -> res.add(f));
        }
    }
    // System.out.println(res);
    return res;
}

Here is my c++ solution, you can watch the explanation here: https://youtu.be/-sX3IgdQ6Wg

vector<int> closestNumbers(vector<int> arr) {
    sort(arr.begin(), arr.end());
    int diff = INT_MAX;
    vector<int> result;
    for(int i = 1; i < arr.size(); i++){
        if(arr[i] - arr[i-1] < diff){
            diff = arr[i] - arr[i-1];
            result = {arr[i-1], arr[i]};
        }
        else if(arr[i] - arr[i-1] == diff){
            result.insert(result.end(), {arr[i-1], arr[i]});
        }
    }
    return result;
}

Here is my Python solution!

def closestNumbers(arr):
    arr = sorted(arr)
    lowest = float("inf")
    minimum = []
    for i in range(len(arr) - 1):
        if arr[i + 1] - arr[i] < lowest:
            lowest = arr[i + 1] - arr[i]
            minimum = [arr[i], arr[i + 1]]
        elif arr[i + 1] - arr[i] == lowest:
            minimum.append(arr[i])
            minimum.append(arr[i + 1])
    return minimum

vector closestNumbers(vector arr) { int n=arr.size(); vectora; sort(arr.begin(),arr.end()); int k; for(int i=0;id; for(int i=0;i