CS 223 - Spring 2017. 4/3

Welcome to CS 223!

Larry Wall Quote of the day

Being an adult isn't about being grown up--it's about realizing you need to grow up.

Logical problem of the day

//version 1
int main(int argc, char *argv[])
{
  bool avl = true;
  if(avl) {
    double x = 123;
  }
}

//version 2
int main(int argc, char *argv[])
{
  bool avl = true;
  if(avl) 
    double x = 123;
}

Is there a meaningful difference between version 1 and version 2?

Lecture 18: HW6 + Data Structures: graphs, heaps

Administrivia

Office hours:

The office hours are Sun/Tue/Thu 8-11 PM at Hillhouse 17 Rm 111.

My office hours this week are Wednesday 4-5pm. (++)

Assignment 5 - Revision

Problem set 5 revision

Add balanced tree option to hw5, using -avl flag.

See /c/cs223/hw5/Cloudavlx

See AVL Trees AVLtree.h AVLtree.c AVLtree.output

Here is one way to do it: (how I did it)

Rewrite AVLtree.h and AVLtree.c to use string keys instead of integer keys. You should test to make sure that this works before going further. (Does not use **root**.)
In the code directory, there are now the following files: AVLmain.h AVLmain.c that give you an idea on how to test the string key version of AVL. The executable, AVLmain, is there. AVLmain.c is just a skeleton - it is missing the code that uses string keys instead of integer keys.

In AVLtree.c, undefine:

#define TEST_MAIN
#define PRINT_AFTER_OPERATIONS

Modify Makefile to create .o file and link in with Cloud:

Cloud:  Cloud.o btree.o AVLtree.o
	${CC} ${CFLAGS} -o Cloud Cloud.o btree.o AVLtree.o

AVLtree.o: AVLtree.c
	${CC} ${CFLAGS} -c AVLtree.c

In AVLtree.h and AVLtree.c, rename functions that conflict with function names in btree.h, e.g., treeHeight() could be avlHeight()
In Cloud.c, check for the -avl command line argument. If present, create an AVL tree. Otherwise, use your btree. Modify your code accordingly, calling the AVL functions or btree functions as appropriate. Also, the avl debug option prints out the tree, unlike the btree option.

Assignment 6

Problem set 6

Per piazza: Can the size of the heap ever be larger than the size of the dictionary?

Final Exam

In class on Monday April 24th. Topics for final exam and Sample questions for final exam (from last year)

Lecture Starts Here

Binary Trees

A btree for integers btreeint.c (from Aspnes) [malloc issue: sizeof(struct node) == sizeof(*newNode) != sizeof(newNode)] -- added treePrint()
A btree for integers btreeintargs.c with command line arguments. -- added treePrint()
The header file btree.h Note: there is no treeDelete function. (sigh of relief)
The test file btreetest.c (continue here) -- added treePrint()
The arg test file btreetestargs.c -- added treePrint()
Data Structure Visualizations
Binary search tree animation
Balanced trees
AVL Trees AVLtree.h AVLtree.c AVLtree.output AVL animation

Heaps and Graphs

heap visualization

heap.c

Aspnes: Heaps Implement heaps as arrays. For zero-based arrays as in C, the rule is that a node at position i has children at positions 2*i+1 and 2*i+2; in the other direction, a node at position i has a parent at position (i-1)/2 (which rounds down in C).

Aspnes: Graphs

Aspnes: 2-3 trees

Aspnes: red black trees

Aspnes: B trees

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