hashtable.c

#include <stdio.h>
#include <stdlib.h>
#include "linkedlist.h"
#include "hashtable.h"

struct hashtable {
    // TODO: define hashtable struct to use linkedlist as buckets

	struct linkedlist** buckets;
	int number_buc;
	int number_maps;
};

/**
 * Hash function to hash a key into the range [0, max_range)
 */
static int hash(int key, int max_range) {
    // TODO: feel free to write your own hash function (NOT REQUIRED)
    key = (key > 0) ? key : -key;
    return key % max_range;
}

hashtable_t *ht_init(int num_buckets) {
    // TODO: create a new hashtable
   
	hashtable_t *hash_tab = (hashtable_t *)malloc(sizeof(hashtable_t));
	hash_tab->buckets = malloc(num_buckets*sizeof(linkedlist_t *));
	for (int i = 0; i < num_buckets; i++) {
		hash_tab->buckets[i] = ll_init();
	}
	hash_tab->number_buc = num_buckets;
	hash_tab->number_maps = 0;
	return hash_tab;
}

void ht_add(hashtable_t *table, int key, int value) {
    // TODO: create a new mapping from key -> value.
    // If the key already exists, replace the value.

	int bucket_num = hash(key, table->number_buc);
	int original_size = ll_size(table->buckets[bucket_num]);
	ll_add(table->buckets[bucket_num], key, value);
	int new_size = ll_size(table->buckets[bucket_num]);
	if (original_size < new_size) {
		table->number_maps++;
	}
	

}


int ht_get(hashtable_t *table, int key) {
    // TODO: retrieve the value mapped to the given key.
    // If it does not exist, return 0

	int bucket_num = hash(key, table->number_buc);
        return ll_get(table->buckets[bucket_num], key);

}

int ht_size(hashtable_t *table) {
    // TODO: return the number of mappings in this hashtable

	return table->number_maps;

}