Q.

Given a list of integers, determine whether the sum of its elements is odd or even.

Give your answer as a string matching "odd" or "even".

If the input array is empty consider it as: [0] (array with a zero).

Examples:
Input: [0]
Output: "even"

Input: [0, 1, 4]
Output: "odd"

Input: [0, -1, -5]
Output: "even"

A)

#include <stddef.h>

const char *odd_or_even(const int *v, size_t sz) {
  int sum = 0;
  for (size_t i = 0; i < sz; i++)
    sum += v[i];
  if (sum < 0)
    sum *= -1;
  return sum % 2 ? "odd" : "even";
}