: A strategy for when two different keys generate the same index (e.g., Separate Chaining ).
We covered:
We'll also implement the hash as an alternative for comparison.
return 0;
curr = curr->next;
#include <stdio.h> #include <stdlib.h> #include <string.h>
| Operation | Average Case | Worst Case (All Collisions) | |-----------|--------------|-------------------------------| | Insert | O(1) | O(n) | | Search | O(1) | O(n) | | Delete | O(1) | O(n) | c program to implement dictionary using hashing algorithms
In open addressing, all entries are stored directly in the hash table array. When a collision occurs, we probe the table for the next available slot using a probe sequence.
djb2 hash function (by Dan Bernstein)
unsigned long hash(char *str) unsigned long hash = 5381; int c; while ((c = *str++)) hash = ((hash << 5) + hash) + c; return hash % TABLE_SIZE; : A strategy for when two different keys
Excellent for low collision rates.
For string keys (common in dictionaries), a popular choice is the (designed by Daniel J. Bernstein), which is simple and yields good distribution:
typedef struct HashTable Node** buckets; int size; HashTable; When a collision occurs, we probe the table
: Find the node in the list and carefully rewire pointers to remove it, then free the memory. 3. Best Practices How to implement a hash table (in C) - Ben Hoyt
This implementation uses a fixed static table size. For production use, dynamic resizing (rehashing) is essential to maintain (O(1)) performance as the dictionary grows.