Minimum Sum of Four Digit Number After Splitting Digits - Problem

#include <stdio.h>
#include <limits.h>
#include <stdlib.h>

int compare(const void *a, const void *b) {
    return (*(int*)a - *(int*)b);
}

int solution(int num) {
    // Extract digits
    int digits[4];
    int temp = num;
    for (int i = 0; i < 4; i++) {
        digits[i] = temp % 10;
        temp /= 10;
    }
    
    // Sort digits to enable optimal distribution
    qsort(digits, 4, sizeof(int), compare);
    
    int minSum = INT_MAX;
    
    // Try all possible ways to split 4 digits into two groups
    for (int mask = 1; mask < 15; mask++) {
        int group1[4], group2[4];
        int g1_size = 0, g2_size = 0;
        
        for (int i = 0; i < 4; i++) {
            if (mask & (1 << i)) {
                group1[g1_size++] = digits[i];
            } else {
                group2[g2_size++] = digits[i];
            }
        }
        
        // Form numbers from groups
        int num1 = 0;
        for (int i = 0; i < g1_size; i++) {
            num1 = num1 * 10 + group1[i];
        }
        
        int num2 = 0;
        for (int i = 0; i < g2_size; i++) {
            num2 = num2 * 10 + group2[i];
        }
        
        if (num1 + num2 < minSum) {
            minSum = num1 + num2;
        }
    }
    
    return minSum;
}

int main() {
    int num;
    scanf("%d", &num);
    int result = solution(num);
    printf("%d\n", result);
    return 0;
}