Modular Data Structure Implementation in C

Implemented Data structures:

• Linked List
• Stack (Linked List based )
• Queue (Linked List based )
• hashMap

#include "DS.h" should get all the data structures included in your program.

typedef struct Node{
    int key;
    int val;
    struct Node *next;

}Node;

typedef struct linkedList{
    Node *head;
    int length;
}linkedList;

• linkedList* create_linked_list(): Creates a linked list and returns a pointer to the linkedList structure
• void append(linkedList* list, int value): insert item at the end of list. O(n)
• int get(linkedList* list, int index): get the value based on index in the list. (returns -234 if not present ) O(n)
• int delete(linkedList* list,int index): Delete the element in list given by index. O(n)
• void print_elements(linkedList* list): Print all elements of list

typedef struct queue{
    Node* front;
    Node* back;
    linkedList* list;
}queue;

• queue* create_queue(): Creates a Queue and returns a pointer to the queue
• void append_queue(queue* q,int value): Adds an item to the end of the queue. O(1)
• int pop_queue(queue* q): removes and returns the item from the front of the queue. (returns -234 if not present ) O(1)
• int get_front(queue* q) : returns the element at the front of the queue. (returns -234 if not present ) O(1)
• int get_back(queue* q): returns the element at the back of the queue. (returns -234 if not present ) O(1)
• void print_queue_elements(): prints all the elements of the queue.

typedef struct stack{
    Node* top;
    linkedList* list;
}stack;

• stack* create_stack(): creates a stack and returns the pointer to the stack.
• void push_stack(stack* st,int item): Adds an item to the top of the stack. O(1)
• int pop_stack(stack* st): Removes and returns the item at the top of the stack. (returns -234 if not present ) O(1)
• int get_top(stack* st): returns the element from the top of the stack. (returns -234 if not present ) O(1)

The structure is pretty much like an array of linkedlists known as hashMap

• hashMap* create_map(): Creates a hashMap and returns the pointer to the map
• void add_item(hashMap* map,int key,int value): Adds a (key,value) pair to the hashMap, hashed based on the key most likely O(1)
• int get_item(hashMap* map,int key): returns the value of key. (returns -234 if not present ) most likely O(1)
• void remove_item(hashMap* map,int key): removes the key value pair from the map most likely O(1)

• Bracket Evaluation using Stack bracketEvaluation.c

• Finding pair in an array that sum to a given value using hashMap sumPair.c