Jeff West - Quiz Section 16 CSE 143 Section AD Quiz Section 16 8/9/2001 Jeff West - Quiz Section 16

Jeff West - Quiz Section 16 Announcements Quiz – Stacks, Queues, Efficiency Homework 5 Demo sign-up… Final Review Sessions next Wednesday and Thursday nights – most likely 7pm both nights, location TBA 8 more days until our summer vacation… 8/9/2001 Jeff West - Quiz Section 16

Jeff West - Quiz Section 16 Agenda Queue Examples From Last Time Circle Drawing Example Efficiency 8/9/2001 Jeff West - Quiz Section 16

Jeff West - Quiz Section 16 Copy Constructor FlightQueue::FlightQueue(FlightQueue& other) { front = back = NULL; Node* curOfOther = other.front; while(curOfOther != NULL) { insert(curOfOther -> myFlight); curOfOther = curOfOther -> next; } 8/9/2001 Jeff West - Quiz Section 16

Jeff West - Quiz Section 16 insert void FlightQueue::insert(const Flight& newFlight) { Node* addMe = new Node; addMe -> myFlight = newFlight; addMe -> next = NULL; if(front == NULL) front = back = addMe; else { back -> next = addMe; back = addMe; } 8/9/2001 Jeff West - Quiz Section 16

Circle Drawing Example The circle drawing program is downloadable from the section AD website under today’s date (8/9/2001). 8/9/2001 Jeff West - Quiz Section 16

Jeff West - Quiz Section 16 Efficiency The idea is to get the “big picture”… If you are running some function on an array of N elements, what does the running time look like… Drop the lowest terms and constants to get the “big picture”… Take the worst case… 8/9/2001 Jeff West - Quiz Section 16

Jeff West - Quiz Section 16 Efficiency Examples N3 + 2N + 5 = O(N3) 9N5 + 8N4 + 3N + 17 = O(N5) Heck, what about these ones? N4 + 18N! + 12N3 = O(____) 2N + 12N – 19 = O(____) 8/9/2001 Jeff West - Quiz Section 16

Efficiency of a Nested Loop for(int i = 0; i < size; i++) for(int j = 0; j < 100; j++) for(int k = j; k < size; k++) cout << “Argh, what fun”; Total cost is O(____) + O(____) + O(____) The algorithm grows like O(____). 8/9/2001 Jeff West - Quiz Section 16

Efficiency of Linear Search int Find(int A[], int N, int x) { for(int i = 0; i < N; i++) { if(A[i] == x) return i; return –1; } A linear search like this grows like O(____). 8/9/2001 Jeff West - Quiz Section 16

Efficiency of Binary Search Binary search deals with an array that is guaranteed to be in sorted order. 1 19 27 36 49 57 62 How much extra effort does it take to search if you double the size of the array? How much effort is saved if you halve the size of the array? 8/9/2001 Jeff West - Quiz Section 16