# 2023-12-06

## Introduction

> **Summary**

> **keywords**

> **TODO**

> **HW**

> **Exercise**\*

> **Next time**

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## Topological Sort

Can be solved by post order DFS. if the input is DAG. directed acyclic graph?\
Start from the node without any dependency.

### Kahn's Algorithm

1. First calculate in-order numbers for each nodes.\
   This helps you to find the minimum dependency nodes.
2. push the no dependency node to the queue.
3. By queue, start a topological sort starting from the popped node.
4. For neighbor nodes, decrease the in-order numbers.
5. go to step 2 until the queue is empty.

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## Test prewrap

* choice diagram.
* table for recursions. tabulations
* practice pseudocode
* huffman coding, put the smaller nodes to the left. (follow the book)
* practice dijstra algortihm with the table.
* limitations of dijstra algorithm, and how you can solve it.
* *
* Terminologies important.
* graph representations important
* *
