《人工智能（一）》

1.a search question includes：a state space. a transition model.  a start state, goal test, path cost function.

2.Search action:

Expand out possible plans

Maintain a frontier of unexpanded plans

Try to expand as few tree nodes as possible

a solution is the sequence of actions(plans),which transforms start state to goal state.

3.策略：深度优先、广度优先。

    3.1广度优先：1.data structure：queue（FIFO）；

                              2.strategy:expend shallowest node first;

    3.2深度优先：1.data structure：stack（LIFO）；

                               2. Strategy: expand deepest node first