def closestNumbers(arr):
    # Write your code here
    arr.sort()
    l1 = []
    mini = abs(arr[0]-arr[1])
    for i in range(len(arr)-1):
        if abs(arr[i]-arr[i+1])<mini:
            mini = abs(arr[i]-arr[i+1])
    for i in range(len(arr)-1):
        if abs(arr[i]-arr[i+1]) == mini:
            l1.append(arr[i])
            l1.append(arr[i+1])
    return l1

fn closest_numbers(arr: &[i32]) -> Vec<i32> {
    //Time complexity: O(n*log(n))
    //Space complexity (ignoring input): O(n)
    let mut arr = arr.to_vec();
    arr.sort_unstable();

    let mut minimun_value = arr[1] - arr[0];
    let mut pairs = vec![arr[0], arr[1]];
    for index in 2..arr.len() {
        if (arr[index] - arr[index - 1]) == minimun_value {
            pairs.push(arr[index - 1]);
            pairs.push(arr[index]);
        }
        if (arr[index] - arr[index - 1]) < minimun_value {
            minimun_value = arr[index] - arr[index - 1];
            pairs = vec![arr[index - 1], arr[index]];
        }
    }
    pairs
}

def closest_numbers(arr):
    # Time complexity: O(n*log(n))
    # Space complexity (ignoring input): O(n)
    arr.sort()
    minimum_diff = arr[1] - arr[0]
    pairs = [arr[0], arr[1]]
    for index in range(2, len(arr)):
        if (arr[index] - arr[index - 1]) == minimum_diff:
            pairs.append(arr[index - 1])
            pairs.append(arr[index])
        if (arr[index] - arr[index - 1]) < minimum_diff:
            minimum_diff = arr[index] - arr[index - 1]
            pairs = [arr[index - 1], arr[index]]

    return pairs

#python 3 solution
from itertools import pairwise

def closestNumbers(arr):
    arr.sort()
    minDiff = max(arr)-min(arr)
    pairs = []
    #finds minimum difference
    for i,j in pairwise(arr):
        minDiff = min(minDiff,j-i)
    #adds pairs with minimum difference to output
    for i,j in pairwise(arr):
        if j-i == minDiff:
            pairs.extend([i,j])
    return pairs

from itertools import pairwise


def closestNumbers(arr: list[int]) -> list[int]:
    pairs = []
    min_diff = float("inf")
    arr.sort()
    for i, j in pairwise(arr):
        if (diff := abs(i - j)) == min_diff:
            pairs += [i, j]
            continue
        if diff < min_diff:
            min_diff = diff
            pairs = [i, j]
    return pairs