1. Midterm review
October 02, 2017
Geoffrey Tien

2. Midterm 1 information October 04, in-class (50 minutes)
Closed book, closed notes
C functions reference sheet provided (see course webpage for sample)
Topics covered
functions, parameters, arrays, loops, strings
pointers & dynamic memory
structures
complexity / asymptotic analysis
By now you should have received a GradeScope invitation to your CS ugrad
Please check and set a password before the exam!
Please remember your CS ugrad ID – you must write it on your exam
October 02, 2017
Geoffrey Tien

3. From sample exam 1
Put these Big-O sets of functions into ascending order of complexity:
𝑂 𝑛 , 𝑂 log 𝑛 , 𝑂 𝑛 , 𝑂 𝑛 , 𝑂 1 𝑛
Solution at course website, but...
A note about 𝑂 1 𝑛
Not really any practical algorithm with this running time – why?
Think about this function's rate of "growth"
October 02, 2017
Geoffrey Tien

4. From sample exam 1 void myCalc(int N) { int w, k; j = 0; n = N;
while (n > 1)
n = n / 32;
j++; }
for (w = 0; w < (N/3 + 32); w++)
for (k = 1; k <= j*N; k++)
printf("$");
This determines how many times the inner loop runs
October 02, 2017
Geoffrey Tien

5. Some other loop forms
Find the most appropriate asymptotic running time of this function
void lotsoloops(int n) {
int i, j, k;
for (i = 0; i < n; i = i+2) {
if (i % 2 == 0) {
for (j = 0; j < n; j = j*2) {
for (k = n; k > 1; k = sqrt(k)) {
printf("$"); }
October 02, 2017
Geoffrey Tien

6. Some other loop forms
What about this function? It looks almost the same
void lotsoloops(int n) {
int i, j, k;
for (i = 0; i < n; i = i+2) {
if (i % 2 == 1) {
for (j = 0; j < n; j = j*2) {
for (k = n; k > 1; k = sqrt(k)) {
printf("$"); }
October 02, 2017
Geoffrey Tien

7. Any more questions?
Good luck!
October 02, 2017
Geoffrey Tien