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| courses:cs211:winter2018:journals:martinj:3.2.6 [2018/02/07 04:12] – martinj | courses:cs211:winter2018:journals:martinj:3.2.6 [2018/02/07 04:55] (current) – martinj | ||
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| ===== Brief summary | ===== Brief summary | ||
| - | 3.2 covered graph connectivity and graph traversal, including breadth-first and depth-first searches, which determine s-t connectivity, | + | 3.2 covered graph connectivity and graph traversal, including breadth-first and depth-first searches, which determine s-t connectivity, |
| - | + | ||
| - | ===== Motivations ===== | + | |
| ===== Algorithms: brief sketches, intuitions, implementations, | ===== Algorithms: brief sketches, intuitions, implementations, | ||
| ==== Breadth-First Search ==== | ==== Breadth-First Search ==== | ||
| Line 27: | Line 25: | ||
| Endif | Endif | ||
| Endfor | Endfor | ||
| - | + | Concepts: | |
| - | + | * Node m is an ancestor of node n if n was marked as explored after m (I think) | |
| - | ===== Questions ===== | + | * If x & y are two nodes that are connected by an edge in the original graph, but not connected its BFS tree, one of them is an ancestor of the other |
| ===== Stuff I want to remember ===== | ===== Stuff I want to remember ===== | ||
| - | + | There are 2 basic ways to represent graphs: | |
| - | ===== How readable / interesting | + | - An adjacency matrix -- requires O(n^2 ) space |
| + | - An adjacency list representation -- requires only O(m+n) space | ||
| + | A queue is a set form which we extract elements in FIFO (first in, first out) order = the order in which they were added | ||
| + | * Stack = same, but opposite (LIFO) | ||
