# C++ Tree and Graph
## Tree

## Graph
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### Topological Sort
* DAG: 有向無環圖
* in degree: 被邊指到的數量
* 依序拿掉 in degree 為 0 的地方
* 拿出得順序就是托墣排序

### Dijkstra

LeetCode Problem

1. The Maze III
2. The Maze II
3. Network Delay Time
4. Cheapest Flights Within K Stops
5. Reachable Nodes In Subdivided Graph
6. Path with Maximum Probability
7. Find the City With the Smallest Number of Neighbors at a Threshold Distance
8. Minimum Cost to Make at Least One Valid Path in a Grid
9. Path With Minimum Effort
10. Number of Restricted Paths From First to Last Node