Why is there no returnSize here?

The answer is a single int, returned by value, so there is no array to allocate and no length to report. returnSize only appears when the result is an array the caller has to free.

Why not use a MAX macro?

#define MAX(a, b) ((a) > (b) ? (a) : (b)) evaluates the winning argument twice, so MAX(solve(...), solve(...)) would run a whole recursion again. A static inline function evaluates each argument once and is type-checked.

What happens if numsSize is 0?

Reading nums[0] then is undefined behaviour: it may return garbage or crash. The statement guarantees at least one element; in other code check numsSize <= 0 first and report the empty case through a flag or an out-parameter.

Can the sum overflow an int?

Not with these bounds: at most 2,000 × 10⁴ = 2 × 10⁷. Signed overflow is undefined behaviour in C, so for larger inputs use long long for here and best (and the return type).

How do I also report where the best run starts and ends?

Add two out-parameters, int* start and int* end. Track from and reset it to i whenever the run restarts; when here beats best, write *start = from and *end = i. For the first example that gives 2 and 5.

Maximum Subarray in C: Brute Force to Kadane's

Q: Can the sum overflow an int?

Not with these bounds: at most 2,000 × 10⁴ = 2 × 10⁷. Signed overflow is undefined behaviour in C, so for larger inputs use long long for here and best (and the return type).

Q: How do I also report where the best run starts and ends?

Add two out-parameters, int* start and int* end. Track from and reset it to i whenever the run restarts; when here beats best, write *start = from and *end = i. For the first example that gives 2 and 5.

max_subarray.c

C 15.3

Not run yet

+ 7 hidden

Input

nums = [4, -6, 3, 5, -2, 6, -9, 1]

Expected

The run [3, 5, -2, 6] sums to 12. The -2 is worth carrying because the 6 after it more than pays it back.