poj2418 （二叉搜尋樹）

        其實這題方法應該還是挺多樣的，trie啦，hash啦等等，bst寫的少，因此就練了練手。

#include <stdio.h>#include <string.h>#include <stdlib.h>typedef struct tNode{char species_name[31];struct tNode* left;struct tNode* right;int count;}Node;Node* root=NULL;char str[31];int total_count=0;Node* create_node(char* str,Node* parent,int left){Node* node=(Node*)malloc(sizeof(Node));strcpy(node->species_name,str);node->left=NULL;node->right=NULL;node->count=1;if(parent){if(left){parent->left=node;}else{parent->right=node;}}return node;}/***search，如果search不到，insert*/void search_insert(Node* node){int result=strcmp(str,node->species_name);if(result==0){node->count++;}if(result>0){if(node->right){search_insert(node->right);}else{create_node(str,node,0);}}if(result<0){if(node->left){search_insert(node->left);}else{create_node(str,node,1);}}}void inorder(Node* node){//按順序輸出結果嘛，當然是中序if(!node){return;}inorder(node->left);printf("%s %.4f\n",node->species_name,100.0*node->count/total_count);inorder(node->right);free(node);}int main(void){while(gets(str)!=NULL){if(root){search_insert(root);}else{root=create_node(str,NULL,0);}total_count++;}inorder(root);return 0;}