BFS 到 Level Order traverse 到 UnionFind 到 Topological Sort 到 Dijkstra 思路总结

BFS 找联通量,找component.

Number of Islands (BFS, DFS 都可以做)

Surrounded Regions (BFS, DFS都可以做)

 

Union Find 找联通量是最合适的方法：对于动态加入的时候，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做的时候，一定要判断edge == nodes - 1, 收集到的node数量是n;

 

Level Order minimum distance 都会用到层级关系；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 （用两个queue，一个收集node，一个收集col的index，min max收集最小col和最大col);

 

==== minimum distance ====== 层级关系；int size = queue.size(); for(int i = 0; i < size; i++);

Walls and Gates

Rotting Oranges 注意到空层的时候，step也加1了，最后return的时候需要减去1；

Word Ladder

Remove Invalid Parentheses

 

 

Topological Sort

Course Schedule

Course Schedule II

 

 

Dijkstra

Pacific Atlantic Water Flow

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