C语言的哈希表

#include "uthash.h"
struct hashTable{
    int key;
    int val;
    UT_hash_handle hh;
};
struct hashTable* hashtable;

struct hashTable* find(int ikey){
    struct hashTable* tmp;
    HASH_FIND_INT(hashtable,&ikey,tmp);
    return tmp;
}

void insert(int ikey, int ival){
    struct hashTable* it = find(ikey);
    if(it == NULL){
        struct hashTable * tmp = malloc(sizeof(struct hashTable));
        tmp->key = ikey, tmp->val=ival;
        HASH_ADD_INT(hashtable,key,tmp);
    }else{
        it->val = ival;
    }
}


int* twoSum(int* nums, int numsSize, int target, int* returnSize) {
    hashtable =  NULL;
    for(int i = 0; i<numsSize; ++i){
        struct hashTable* it = find(target-nums[i]);
        if(it != NULL){
            int* ret = malloc(sizeof(int)*2);
            ret[0] = it->val, ret[1] = i;
            *returnSize = 2;
            return ret;
        }
        insert(nums[i],i);
    }
    *returnSize = 0;
    return NULL;
}