The use and difference of BFS and DFS

1.BFS is used to search the shortest path of the solution is more appropriate, such as the minimum number of steps to solve the solution, the minimum number of exchanges, because the solution encountered in the BFS search process must be closest to the root, so encountered a solution, must be the optimal solution, at this time the search algorithm can terminate. DFS is not appropriate at this time, because the solution to DFS search is not necessarily the closest to the root, and only the global search is complete to find the closest solution to the root from all the solutions. (Of course this DFS is not enough, you can use iterative deepen search Id-dfs to make up)
2. In space, DFS is advantageous, DFS does not need to save the state of the search process, while BFS in the search process needs to save the status of the search, and the general situation requires a queue to record.
3.DFS is suitable for searching all solutions, because to search all of the solution, then BFS search process, encounter the root of the most recent solution, and there is no use, you must traverse the entire tree search, Dfs search will also search all, but compared to DFS do not record too much information, so search the whole solution of the problem, DFS is clearly more appropriate.

Author: Know the user
Link: https://www.zhihu.com/question/23780297/answer/167225829
Source: Know
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