Create LinkedList.c

C/data_structures/LinkedList.c

@@ -0,0 +1,140 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+/*
+Problem:
+Implement a Singly Linked List that allows insertion, deletion, and display operations.
+Each node contains an integer value and a pointer to the next node.
+*/
+
+// Define the structure for a linked list node
+struct Node {
+    int data;              // Stores the data value
+    struct Node* next;     // Pointer to the next node
+};
+
+// Function to create a new node with the given value
+struct Node* createNode(int value) {
+    struct Node* newNode = (struct Node*)malloc(sizeof(struct Node));  // Allocate memory
+    if (newNode == NULL) {  // Check for memory allocation failure
+        printf("Memory allocation failed!\n");
+        exit(1);
+    }
+    newNode->data = value;  // Set data value
+    newNode->next = NULL;   // Initialize next pointer as NULL
+    return newNode;
+}
+
+// Function to insert a new node at the end of the linked list
+void insertEnd(struct Node** head, int value) {
+    struct Node* newNode = createNode(value);  // Create new node
+    if (*head == NULL) {   // If list is empty, make newNode the head
+        *head = newNode;
+        return;
+    }
+
+    // Traverse to the end of the list
+    struct Node* temp = *head;
+    while (temp->next != NULL) {
+        temp = temp->next;
+    }
+
+    // Link the new node at the end
+    temp->next = newNode;
+}
+
+// Function to display all elements of the linked list
+void display(struct Node* head) {
+    struct Node* temp = head;
+    printf("Linked List: ");
+    while (temp != NULL) {
+        printf("%d -> ", temp->data);  // Print current node data
+        temp = temp->next;             // Move to next node
+    }
+    printf("NULL\n");
+}
+
+// Function to delete a node by its value
+void deleteNode(struct Node** head, int value) {
+    struct Node *temp = *head, *prev = NULL;
+
+    // Case 1: If the list is empty
+    if (*head == NULL) {
+        printf("List is empty. Nothing to delete.\n");
+        return;
+    }
+
+    // Case 2: If the node to be deleted is the head
+    if (temp != NULL && temp->data == value) {
+        *head = temp->next; // Move head to next node
+        free(temp);         // Free memory of deleted node
+        return;
+    }
+
+    // Case 3: Search for the node to delete
+    while (temp != NULL && temp->data != value) {
+        prev = temp;
+        temp = temp->next;
+    }
+
+    // If node not found
+    if (temp == NULL) {
+        printf("Value %d not found in list.\n", value);
+        return;
+    }
+
+    // Unlink and delete the node
+    prev->next = temp->next;
+    free(temp);
+}
+
+// Main function to demonstrate linked list operations
+int main() {
+    struct Node* head = NULL; // Initialize an empty linked list
+
+    // Insert some nodes
+    insertEnd(&head, 10);
+    insertEnd(&head, 20);
+    insertEnd(&head, 30);
+
+    // Display the linked list
+    display(head); // Expected Output: 10 -> 20 -> 30 -> NULL
+
+    // Delete a node with value 20
+    deleteNode(&head, 20);
+
+    // Display list after deletion
+    display(head); // Expected Output: 10 -> 30 -> NULL
+
+    return 0;
+}
+
+/*
+----------------------------------------
+Algorithm Explanation:
+----------------------------------------
+1. Create Node:
+   - Dynamically allocate memory for each node.
+   - Store the data and set 'next' pointer as NULL.
+
+2. Insert at End:
+   - Traverse to the last node.
+   - Link the newly created node at the end.
+
+3. Delete by Value:
+   - Search for the node with the given value.
+   - Adjust links to remove the node and free its memory.
+
+4. Display:
+   - Traverse through the list and print each node’s data.
+
+----------------------------------------
+Time & Space Complexities:
+----------------------------------------
+Operation           Time Complexity      Space Complexity
+---------------------------------------------------------
+Insertion (End)     O(n)                 O(1)
+Deletion (By Value) O(n)                 O(1)
+Traversal/Display   O(n)                 O(1)
+----------------------------------------
+*/