1. Data Structures and Algorithms I
CMP 338
Data Structures and Algorithms I
Day 13, 10/18/11
Balanced Search Trees

2. Good Pivot int goodPivot(double[] a, int lo, int hi) int n = hi-lo+1,
for (int i=0; i<n/5; i++)
median5(a, lo+i*5)
exch(a, lo+i, lo+i*5+2)
select(a, lo, lo+n/5-1, lo+n/10)
return lo+n/10
void median5(double a, int n)
for (int i=n; i<n+3; i++)
for (int j=i+1; j<n+5)
if (a[j]<a[i]) exch(a, i, j)

3. Homework 10, due noon 10/21 Improve quicksort (any variant)
Use insertion sort to sort small regions
static void setSmall(int s)
static int getSmall()
Find the best value for small
Turn in (include your name in a comment)
a) working code for your program Homework10.java
b) performance numbers (standard out) hw10.txt
c) performance graphs hw10.doc or hw10.odt
d) your interpretation of the data hw10.doc or hw10.odt

4. Improved Quicksort? quicksort(double[] a) // StdRandom.shuffle(a);
quicksort(a, 0, ||a||-1)
if (0 < small) insertionSort(a)
quicksort(double[] a, int lo, int hi)
if (hi<=lo + small) return;
int j = partition(a, lo, hi)
sort(a, lo, j-1)
sort(a, j+1, hi)