struct Entry {
    int id;            /* we'll use this field as the key */
    int val;
    UT_hash_handle hh; /* makes this structure hashable */
};

struct Entry *g_users = NULL;
int* twoSum(int* nums, int numsSize, int target, int* returnSize){
    int *res = (int *)calloc(2, sizeof(int));
    *returnSize = 2;
    g_users = NULL;
    for (int i = 0; i < numsSize; i++) {
        struct Entry *s = (struct Entry *)calloc(1, sizeof(struct Entry));
        struct Entry *tmp = NULL;
        int r = target - nums[i];
        HASH_FIND_INT(g_users, &r, tmp);
        if (tmp != NULL) {
            res[0] = tmp->val, res[1] = i;
            return res;
        }
        s->id = nums[i];
        s->val = i;
        HASH_ADD_INT(g_users, id, s);
    }
    return res;
}