Add initial linked list implementation

3 files changed, 218 insertions, 0 deletions

diff --git a/linkedlist/ll.c b/linkedlist/ll.c
new file mode 100644
index 0000000..43bfa27
--- /dev/null
+++ b/linkedlist/ll.c
@@ -0,0 +1,120 @@
+// Implementation of a Linked List
+#include <stdio.h>
+#include <stdlib.h>
+#include "ll.h"
+
+Node* llnode() {
+	Node* n = (Node*) malloc(sizeof(Node));
+	n->value = 0;
+	n->next = NULL;
+	return n;
+}
+
+void llprint(Node* head) {
+	Node* node = head;
+	printf("[ ");
+	do {
+		printf("%i ", node->value);
+		node = node->next;
+	} while (node != NULL);
+	printf("]\n");
+}
+
+void llvprint(Node* head) {
+	Node* node = head;
+	do {
+		printf("[*] %i\n", node->value);
+		node = node->next;
+		printf(" |\n");
+	} while (node != NULL);
+	printf("[/] %p\n", node);
+}
+
+int llcount(Node* head) {
+	Node* node = head;
+	int count = 0;
+	while (node != NULL) {
+		count++;
+		node = node->next;
+	}
+	return count;
+}
+
+void llappend(Node* head, int value) {
+	Node* n = head;
+	while (n->next != NULL) n = n->next;
+	n->next = NEW_NODE;
+	n->next->value = value;
+	n->next->next = NULL;
+}
+
+void llpush(Node** head, int value) {
+	Node* n = NEW_NODE;
+	n->value = value;
+	n->next = *head;
+	*head = n;
+}
+
+void llinsert(Node** head, int value, int index) {
+	Node* n = *head;
+	Node* cur = NULL;
+	Node* node = NEW_NODE;
+	int i = 0;
+	node->value = value;
+	while (n->next != NULL && i < index) {
+		cur = n;
+		n = n->next;
+		++i;
+	}
+	cur->next = node;
+	node->next = n;
+}
+
+void llfree(Node* head) {
+	Node* n = NULL;
+	while (head != NULL) {
+		n = head;
+		head = head->next;
+		free(n);
+	}
+}
+
+int llpop(Node** head) {
+	Node* n = *head;
+	int val = n->value;
+	*head = n->next;
+	free(n);
+	return val;
+}
+
+int llrmlast(Node** head) {
+	Node* n = *head;
+	Node* cur = NEW_NODE;
+	while (n->next != NULL) {
+		cur = n;
+		n = n->next;
+	}
+	int val = n->value;
+	cur->next = NULL;
+	free(n);
+	return val;
+}
+
+int llrm(Node** head, int index) {
+	Node* n = *head;
+	Node* cur = NEW_NODE;
+	Node* node = NEW_NODE;
+	int i = 0;
+	int val = 0;
+	while (n->next != NULL && i < index) {
+		cur = n;
+		n = n->next;
+		++i;
+	}
+	cur->next = n->next;
+	node->next = n;
+	val = n->value;
+	free(n);
+	return val;
+}
+
diff --git a/linkedlist/ll.h b/linkedlist/ll.h
new file mode 100644
index 0000000..0e15c43
--- /dev/null
+++ b/linkedlist/ll.h
@@ -0,0 +1,54 @@
+#ifndef LL
+#define LL
+
+#define NEW_NODE llnode();
+
+#include <stdio.h>
+#include <stdlib.h>
+
+// Node
+typedef struct Node {
+	int value;
+	struct Node* next;
+} Node;
+
+// Create & initialise a new node
+Node* llnode();
+
+// Print linked list values
+// O()
+void llprint(Node* head);
+void llvprint(Node* head);
+
+// Return number of nodes in list
+// O(n)
+int llcount(Node* head);
+
+// Append value to the end of the list
+// O(n)
+void llappend(Node* head, int value);
+
+// Prepend a value to the list
+// O(1)
+void llpush(Node** head, int value);
+
+// Insert a value to the list at index
+// O(n)
+void llinsert(Node** head, int value, int index);
+
+// Free nodes from memory
+void llfree(Node* head);
+
+// Pop (remove) first node
+// O(1)
+int llpop(Node** head);
+
+// Remove last node
+// O(n)
+int llrmlast(Node** head);
+
+// Remove node at index
+// O(n)
+int llrm(Node** head, int index);
+
+#endif //LL
diff --git a/linkedlist/main.c b/linkedlist/main.c
new file mode 100644
index 0000000..3ba95a3
--- /dev/null
+++ b/linkedlist/main.c
@@ -0,0 +1,44 @@
+#include "ll.h"
+
+int main() {
+	Node* head = NEW_NODE;
+	int val;
+
+	val = 7;
+	head->value = val;
+	printf("Init with %i:\t", val);
+	llprint(head);
+
+	val = 12;
+	llpush(&head, val);
+	printf("Push %i:\t", val);
+	llprint(head);
+
+	val = 99;
+	printf("Append %i:\t", val);
+	llappend(head,val);
+	llprint(head);
+
+	val = 45;
+	printf("Insert %i:\t", val);
+	llinsert(&head, val, 2);
+	llprint(head);
+
+	val = 42;
+	printf("Insert %i:\t", val);
+	llinsert(&head, val, 1);
+	llprint(head);
+
+	printf("Pop %i:\t\t", llpop(&head));
+	llprint(head);
+
+	printf("Remove %i:\t",llrmlast(&head));
+	llprint(head);
+
+	printf("Remove %i:\t",llrm(&head,1));
+	llprint(head);
+
+	llvprint(head);
+
+	llfree(head);
+}