Differences
This shows you the differences between two versions of the page.
Both sides previous revisionPrevious revisionNext revision | Previous revision | ||
courses:cs211:winter2011:journals:chen:chapter_2 [2011/01/25 01:38] – [2.4 A Survey of Common Running Times] zhongc | courses:cs211:winter2011:journals:chen:chapter_2 [2011/01/25 01:52] (current) – [2.3 Implementing the Stable Matching Algorithm Using Lists and Arrays] zhongc | ||
---|---|---|---|
Line 51: | Line 51: | ||
Refer back to the 1/17 slide for the breakdown of the running time of O(N²) of the the total running time. | Refer back to the 1/17 slide for the breakdown of the running time of O(N²) of the the total running time. | ||
+ | |||
+ | |||
+ | Interesting/ | ||
===== 2.4 A Survey of Common Running Times ===== | ===== 2.4 A Survey of Common Running Times ===== | ||
Line 83: | Line 86: | ||
Independent set of size k. Given a graph,are there k nodes such that no two are joined by an edge? | Independent set of size k. Given a graph,are there k nodes such that no two are joined by an edge? | ||
+ | Note: Summary of running times. P20 slide 1/19 | ||
+ | |||
+ | |||
+ | Interesting/ | ||
+ | ===== 2.5 A More Complex Data Structure: | ||
+ | Motivation: | ||
+ | **After overcoming higher-level obstacles, | ||
+ | lower-level implementation details | ||
+ | can improve runtime.** | ||
+ | |||
+ | Summary | ||
+ | Priority Queue revisited: | ||
+ | |||
+ | Maintains a set of elements S | ||
+ | • Each element v ∈ S has a key(v) for its priority | ||
+ | Smaller keys represent higher priorities | ||
+ | Supported operations | ||
+ | • Add, delete elements | ||
+ | • Select element with smallest key | ||
+ | |||
+ | Implementing data structures: for sorting | ||
+ | If we use unsorted lists: N² -why? | ||
+ | |||
+ | If we use array: logn*N² | ||
+ | |||
+ | If we use heaps: NlogN | ||
+ | |||
+ | Implementation of Heaps: | ||
+ | Know the implementation of the **Heapify-up** and **Heapify-down** with an array based implementation. | ||
+ | Interesting/ | ||
+ |