BFS 到 Level Order traverse 到 UnionFind 到 Topological Sort 到 Dijkstra 思路總結

BFS 找聯通量,找component.

Number of Islands (BFS, DFS 都可以做)

Surrounded Regions (BFS, DFS都可以做)

 

Union Find 找聯通量是最合適的方法：對於動態加入的時候，尤其有效果；

Number of Connected Components in an Undirected Graph (BFS,  DFS, Union Find 都可以做)

Graph Valid Tree (BFS, Union Find 都可以做) BFS做的時候，一定要判斷edge == nodes - 1, 收集到的node數量是n;

 

Level Order minimum distance 都會用到層級關係；int size = queue.size(); for(int i = 0; i < size; i++);

Binary Tree Level Order Traversal

Binary Tree Level Order Traversal II

Binary Tree Zigzag Level Order Traversal

Binary Tree Vertical Order Traversal （用兩個queue，一個收集node，一個收集col的index，min max收集最小col和最大col);

 

==== minimum distance ====== 層級關係；int size = queue.size(); for(int i = 0; i < size; i++);

Walls and Gates

Rotting Oranges 注意到空層的時候，step也加1了，最後return的時候需要減去1；

Word Ladder

Remove Invalid Parentheses

 

 

Topological Sort

Course Schedule

Course Schedule II

 

 

Dijkstra

Pacific Atlantic Water Flow

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