Download Linked Lists and Data Structures: Lecture 12 in CMSC 212 - Prof. Jandelyn Dawn Plane and more Study notes Computer Science in PDF only on Docsity!
Announcements
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Exam #1 and Project #1– if you have not picked something up, see me after class
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Exam #1 Re-grade Requests– due by end of class today (both electronic and paper)
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Program #2– Due on March 15 at 8:00 pm (Tuesday)– Don’t free NULL pointers – will be flagged as an error and
cause you to fail tests
- createTable – confusion about interpretation
- passing in a “size” just needs to be in range• does not need to be exactly one of the primes in the list
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Reading– Chapter 12, 10.2 (Today)– Notes (Tuesday)
Linked Data Structures
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Like classes with refs to same class in Java
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Have pointers to a struct of the same time
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Example Declaration:typedef struct NODE {
struct NODE *next;int value;
} Node;
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Next is a pointer to another Node root
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10
15 NULL
Tracing Through Insert
head
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10
15
X^7
Insert 7
X 2
Insert 2
NULL
Inserting Into a Linked List
**int insert(Node head, int new_value) {
**Node *current = *head;Node pred = NULL;Node newItem;while (current && current->value < new_value) {
pred = current;current = current->next;
*} newItem = (Node ) malloc(sizeof(Node));if (!newItem) return -1;newItem->value = new_value;newItem->next = current;if (!pred) {
*head = newItem;
} else {
pred->next = newItem;
} return 0;
}
Deleting From A Single Linked List
**int delete(Node head, int new_value) {
**Node *pred = NULL;Node current = head;while (current && (current->value != new_value)) {
pred = current;current = current->next;
} if (!current) {
return -1;
/ not found /
} if (pred) {
pred->next = current->next; } else {
*head = current->next; / deleted first item / } free (current);return 0;
}
Doubled Linked Lists
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Each nodes– contains a value– a pointer the next
and
previous element
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Typical Declaration:typedef struct NODE {
struct NODE *next;struct NODE *prev;int value; } Node; root
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10
15
NULL
NULL
Inserting Into A Doubly Linked List
**int insert(Node head, int new_value) {
**Node *pred = NULL, *newItem;Node current = head;while (current && current->value < new_value) {
pred = current;current = current->next;
*} newItem = (Node ) malloc(sizeof(Node));if (!newItem) return -1;newItem->value = new_value;newItem->next = current;newItem->prev = pred;if (!pred) {
*head = newItem;
} else {
pred->next = newItem;
} if (current) {
current->prev = next; }
}
Deleting from a Doubly Linked List
**int delete(Node head, int new_value) {
**Node *pred = NULL;Node current = head;while (current && (current->value != new_value)) {
pred = current;current = current->next;
} if (!current)
return -1;
/ not found /
if (pred) {
pred->next = current->next; } else {
*head = current->next; / deleted first item / } if (current->next) {
current->next->prev = pred; } free (current);return 0;
}
Lookup In A Binary Search Tree
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If the element is less than the current node– Look in the left child tree
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If the element is greater than current node– Look in the right child tree
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Example (assumes values >= 0):^ int Lookup(Node *root, int value) {
if (!root) return -1;if (root->value == value) {
return 1; } else if (root->value > value) {
return Lookup(root->left, value); } else {
return Lookup(root->right, value); } }
Insert Into a Binary SearchTree
**int insert(Node root, int value) {
Node new;if (!(root)) {
new = (Node ) malloc(sizefof(Node));if (!new) return -1;root = new;new->left = new->right = NULL;new->value = value;return 0; } if ((root)->value > value) {*
return insert(&((root)->left), value);*
} else {
return insert(&((root)->right), value);*
}
}
Graphs
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Null
Null
Node^ Arc
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14
key
Adding Node To a Graph
*Node AddNode(int value) {
**Node new;new = (Node ) malloc(sizeof(Node));new->value = value;new->outArcs = NULL;return new; } You need to store this node into some type of structure so you don’t lose it
linked list of nodesarray of nodestree of nodesetc.
