Embed Size (px)
DESCRIPTION
Trees. What is a tree?. You know… tall green leafy possibly fruit branches roots I’m sure you’ve seen them. In the context of C (and CS in general). Trees are a Data Structure (Like a linked list) They Are upside-down Have one root Have branches Have leaves (No fruit). - PowerPoint PPT Presentation
Citation preview
Trees
What is a tree?
You know… tall green leafy possibly fruit branches roots I’m sure you’ve
seen them
In the context of C (and CS in general)
Trees are a Data Structure (Like a linked list)
They Are upside-down Have one root Have branches Have leaves (No fruit)
A Tree (In general)
Nodes
Edges (Links (Pointers))
The Root
Leaves
Branches (A.K.A. Sub-Trees)
Branches (A.K.A. Sub-Trees)
Branches (A.K.A. Sub-Trees)
Parent / Children
Some info
The root has no parent
The leaves have no children
The interior nodes have at least one child, and a parent
Types of trees
Binary trees Every node has (at most) two childen
Trinary trees Every node has (at most) three childen
N-ary trees Every node has as many children as it
wants/needs
We care about binary trees
Binary search trees
97
58
26
34 42
517
68 79
70
37
24 83
48 65
31
18
55
Binary Trees
typedef struct S_tree
{
int value; // For example
struct S_tree *left, *right;
} tree;
Just like a linked list, but instead of one pointer, it has two! (left and right)
In Order Traversal
Printing an entire binary search tree.
void print_tree(tree *t) {
if (t == NULL)return;
print_tree(t->left);printf(“%d\n”,t->val);print_tree(t->right);
}
Recursion!
Traversing a Tree
26
34 42
517
37
24
48
31
18
Start with the root.
Traverse Left SubtreePrint Node ValueTraverse Right Subtree
Traversing a Tree
26
34 42
517
37
24
48
31
18
Start with the root.
Traverse Left SubtreePrint Node ValueTraverse Right Subtree
Traversing a Tree
26
34 42
517
37
24
48
31
18
Start with the root.
Traverse Left SubtreePrint Node ValueTraverse Right Subtree
7
Traversing a Tree
26
34 42
517
37
24
48
31
18
Start with the root.
Traverse Left SubtreePrint Node ValueTraverse Right Subtree
7 18
Traversing a Tree
26
34 42
517
37
24
48
31
18
Start with the root.
Traverse Left SubtreePrint Node ValueTraverse Right Subtree
7 18 24
Traversing a Tree
26
34 42
517
37
24
48
31
18
Start with the root.
Traverse Left SubtreePrint Node ValueTraverse Right Subtree
7 18 24 26
Traversing a Tree
26
34 42
517
37
24
48
31
18
Start with the root.
Traverse Left SubtreePrint Node ValueTraverse Right Subtree
7 18 24 26 31
Traversing a Tree
26
34 42
517
37
24
48
31
18
Start with the root.
Traverse Left SubtreePrint Node ValueTraverse Right Subtree
7 18 24 26 31 34
Traversing a Tree
26
34 42
517
37
24
48
31
18
Start with the root.
Traverse Left SubtreePrint Node ValueTraverse Right Subtree
7 18 24 26 31 34 37
Traversing a Tree
26
34 42
517
37
24
48
31
18
Start with the root.
Traverse Left SubtreePrint Node ValueTraverse Right Subtree
7 18 24 26 31 34 37 42
Traversing a Tree
26
34 42
517
37
24
48
31
18
Start with the root.
Traverse Left SubtreePrint Node ValueTraverse Right Subtree
7 18 24 26 31 34 37 42 48
Traversing a Tree
26
34 42
517
37
24
48
31
18
Start with the root.
Traverse Left SubtreePrint Node ValueTraverse Right Subtree
7 18 24 26 31 34 37 42 48 51
Traversing a Tree
26
34 42
517
37
24
48
31
18
Start with the root.
Traverse Left SubtreePrint Node ValueTraverse Right Subtree
7 18 24 26 31 34 37 42 48 51
