Zusammenfassung der Ressource
Decision 1
- Chapter 1 ~ Algorithms
- Following instructions
- Flow chart
- Start/End
- Instruction
- Decision
- Sorts
- Bubble
- Compare adjacent items
- "Passes"
- Quick
- Pivots to create sub-lists
- (n+1)/2 and round up if
necessary to find pivots
- Binary Search
- Search an ordered list
- Select middle item using (n+1)/2
and round up if necessary
- Consider it compared
to value searching for
- Bin Packing
- First-fit
- In order given
- Quick but not likely
to lead to a good
solution
- First-fit decreasing
- With a list in descending order
- Fairly good solution but not always optimal
- Full-bin
- Uses observation to fill bins
- Good solution but difficult,
especially with lots of numbers
- Chapter 2 ~ Graphs and Networks
- Points - Nodes/Vertices
- List is called
the vertex set
- Lines - Arcs/Edges
- If numbers associated, it is a
weighted graph or network
- List is called the edge set
- Terms: Subgraph,
Degree/Valency/Order, Path,
Walk, Cycle/Circuit
- Connected, Loop, Simple
Graph, Directed Edges, Digraph
- Trees/Spanning Tree
- (Complete) Bipartite and
Complete graphs
- Isomorphic graphs
- Adjacency and distance matrices
- Chapter 3 ~ Algorithms on Networks
- Minimum Spanning
Tree (no cycles)
- Kruskal's
- Using ascending weights
- Prim's
- Least weight from chosen vertex
- Easily done with a distance matrix
- Dijkstra's Alorithm
- Shortest path between two vertices
- Select smallest working value
- Work backwards to find path
- Chapter 4 ~ Route Inspection (Chinese Postman)
- Is a graph traversable?
- If all of the valencies in a graph
are even, the that graph is
Eulerian and therefore traversable
- If the graph has just two valencies that are odd, then
the graph is semi-Eulerian. In this case, the start and
finish points will be the two vertices with odd valencies
- A graph is not traversable if it has more than two odd valencies
- Finding the shortest route in a network
- For semi-Eulerian graph,
the shortest path between
the two odd vertices will
have to be repeated
- Algorithm
- 1 ~ Identify any vertices with odd valency
- 2 ~ Consider all possible pairings of these vertices
- 3 ~ Select the complete pairing that has the least sum
- 4 ~ Add a repeat of the arcs indicated
by this pairing to the network
- Traversable ~ sum of each arc's weight will be the weight of the network
- Chapter 5 ~ Critical Path Analysis
- Precedence Table/Dependence Table
- Shows what
must be
completed for
an activity to
start
- Used to create activity network
- 0 node ~ source node
- Last node ~ sink node
- Often can take a couple of
times to get layout correct
- Dummies
- Each activity must be
uniquely represented
- C depends on A but D
depends on A and B
- Early and Late event times
- Early ~ use largest number
- From a forward pass/forward scan
- Late ~ use smallest number
- From a backward pass/backward scan
- Total float = latest finish time -
duration - earliest start time
- Cascade (Gantt) Charts
- Shows time leeway
- Dotted box represents float
- Look halfway before to see how many activities
- Consider float
- Critical activities
- Change to time would impact overall time
- At each node, early event time = late event time
- Critical path
- Chapter 6 ~ Linear Programming
- Chapter 7 ~ Matchings