Minimum Sum of Four Digit Number After Splitting Digits

Problem Description

Ah, the classic dilemma of splitting digits to achieve the minimum sum! Imagine you have a four-digit number, and you’re tasked with splitting its digits into two two-digit numbers. Sounds simple, right? Well, it’s like trying to divide a pizza among friends who can’t agree on toppings. You want to minimize the sum of those two numbers, but everyone has their own preferences!

In this problem, you’re given a four-digit integer, and your mission, should you choose to accept it, is to rearrange its digits to form two new two-digit numbers that yield the smallest possible sum. It’s like trying to find the best way to split the bill at a restaurant without causing a food fight!

Code Solution


class Solution {
 public:
  int minimumSum(int num) {
    string s = to_string(num);
    ranges::sort(s);
    return stoi(s.substr(0, 1) + s.substr(2, 1)) +
           stoi(s.substr(1, 1) + s.substr(3, 1));
  }
};

Approach

The approach here is straightforward yet elegant. First, we convert the four-digit number into a string to easily access each digit. Then, we sort the digits in ascending order. By doing this, we can pair the smallest digits together to form the two two-digit numbers. Finally, we calculate the sum of these two numbers and return it. It’s like organizing a group of friends by height to ensure the shortest ones get the best view!

Time and Space Complexity

Complexity Type	Complexity
Time Complexity	O(1)
Space Complexity	O(1)

Real-World Example

Let’s say you’re at a party with four friends, and you want to split the cost of snacks. If the total cost is represented by the number 4312, you could split it into two groups: 12 and 43. The total cost would be minimized, and everyone leaves happy (or at least with full stomachs).