Very Easy O(1) Time complexity solution 
Intuition

Extract and Sort the Digits:
Break the 4-digit number into its digits and sort them in ascending order. Sorting ensures smaller digits can be placed
# Intuition
<!-- Describe your first thoughts on how to solve this problem. -->
1. Extract and Sort the Digits:
Break the 4-digit number into its digits and sort them in ascending order. Sorting ensures smaller digits can be placed in more significant positions to minimize the sum.

2. Form Two Numbers Alternately:
Distribute the sorted digits alternately between two numbers. Start with the smallest digit in the tens place of one number, then the next smallest in the tens place of the other number, and so on.

3. Calculate the Minimum Sum:
Combine the digits to form the two numbers and return their sum. This ensures the smallest possible sum for the given digits.


# Approach
<!-- Describe your approach to solving the problem. -->
1. Make a empty list 
2. Extract the digits from the number and store them in your list.
3. Sort the list.
4. Then make two variables num1 and num2.
5. Make the combination of first digit with the last one as the last one is the maximum one so we can't put it in one's place so we put it with the smallest one.
6. Now complete your answer.
# Complexity
- Time complexity: O(1)
<!-- Add your time complexity here, e.g. $$O(n)$$ -->

- Space complexity: O(1)
<!-- Add your space complexity here, e.g. $$O(n)$$ -->

# Code
```python3 []
class Solution:
    def minimumSum(self, num: int) -> int:
        l=[]
        while num!=0:
            l.append(num%10)
            num//=10
        l.sort()
        num1=(l[0]*10)+l[3]
        num2=(l[1]*10)+l[2]
        return num1+num2
```
['Math', 'Sorting', 'Python', 'Python3']