8. The method of claim 3 , wherein calculating the clicking cost of the navigation hierarchical structure diagram based at least in part on confidence levels of the leaf nodes and hierarchical positions corresponding to the leaf nodes includes: adding products of corresponding confidence levels and hierarchical positions in the navigation hierarchical structure diagram for all leaf nodes of the navigation hierarchical structure diagram.
8. The method of claim 3 , wherein calculating the clicking cost of the navigation hierarchical structure diagram based at least in part on confidence levels of the leaf nodes and hierarchical positions corresponding to the leaf nodes includes: adding products of corresponding confidence levels and hierarchical positions in the navigation hierarchical structure diagram for all leaf nodes of the navigation hierarchical structure diagram. 9. The method of claim 8 , wherein calculating the clicking cost c_cost ij of the navigation hierarchical structure diagram includes using: c_cost ij = c_cost ⁢ ( query i , tr j ) = ∑ k = 1 K ⁢ level k * h ⁡ ( query i , leaf_cat k ) wherein: query i , represents search request i; tr i represents the jth navigation hierarchical structure diagram; leaf_cat k represents the kth leaf node of the jth navigation hierarchical structure diagram; level k represents the hierarchical position where leaf_cat k is located in jth navigation hierarchical structure diagram; h(query i ,v_cat k ) represents the confidence level for leaf_cat k ; and K is the total number of leaf nodes in the jth navigation hierarchical structure diagram.