int *build_array(char **strs, int size) {
        int *ptr = malloc(sizeof(int) * size);
        for (int i = 0; i < size; i++){
                ptr[i] = (int) strtol(strs[i], NULL, 10);
        }
        return ptr;
}

Return a pointer to an array of ints with size elements.
   - strs is an array of strings where each element is the string
     representation of an integer.
   - size is the size of the array