POJ 2418 Hardwood Species （二叉查找树--插入操作）

左手的ㄟ右手 2024-02-17 21:19 4阅读 0赞

Hardwood Species

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 <tbody> 
  <tr> 
   <td><strong>Time Limit:</strong> 10000MS</td> 
   <td>&nbsp;</td> 
   <td><strong>Memory Limit:</strong> 65536K</td> 
  </tr> 
  <tr> 
   <td><strong>Total Submissions:</strong> 24658</td> 
   <td>&nbsp;</td> 
   <td><strong>Accepted:</strong> 9530</td> 
  </tr> 
 </tbody> 
</table>

Description

Hardwoods are the botanical group of trees that have broad leaves, produce a fruit or nut, and generally go dormant in the winter.  
America's temperate climates produce forests with hundreds of hardwood species -- trees that share certain biological characteristics. Although oak, maple and cherry all are types of hardwood trees, for example, they are different species. Together, all the hardwood species represent 40 percent of the trees in the United States.  
  
On the other hand, softwoods, or conifers, from the Latin word meaning "cone-bearing," have needles. Widely available US softwoods include cedar, fir, hemlock, pine, redwood, spruce and cypress. In a home, the softwoods are used primarily as structural lumber such as 2x4s and 2x6s, with some limited decorative applications.  
  
Using satellite imaging technology, the Department of Natural Resources has compiled an inventory of every tree standing on a particular day. You are to compute the total fraction of the tree population represented by each species.

Input

Input to your program consists of a list of the species of every tree observed by the satellite; one tree per line. No species name exceeds 30 characters. There are no more than 10,000 species and no more than 1,000,000 trees.

Output

Print the name of each species represented in the population, in alphabetical order, followed by the percentage of the population it represents, to 4 decimal places.

Sample Input

Red Alder
    Ash
    Aspen
    Basswood
    Ash
    Beech
    Yellow Birch
    Ash
    Cherry
    Cottonwood
    Ash
    Cypress
    Red Elm
    Gum
    Hackberry
    White Oak
    Hickory
    Pecan
    Hard Maple
    White Oak
    Soft Maple
    Red Oak
    Red Oak
    White Oak
    Poplan
    Sassafras
    Sycamore
    Black Walnut
    Willow

Sample Output

Ash 13.7931
    Aspen 3.4483
    Basswood 3.4483
    Beech 3.4483
    Black Walnut 3.4483
    Cherry 3.4483
    Cottonwood 3.4483
    Cypress 3.4483
    Gum 3.4483
    Hackberry 3.4483
    Hard Maple 3.4483
    Hickory 3.4483
    Pecan 3.4483
    Poplan 3.4483
    Red Alder 3.4483
    Red Elm 3.4483
    Red Oak 6.8966
    Sassafras 3.4483
    Soft Maple 3.4483
    Sycamore 3.4483
    White Oak 10.3448
    Willow 3.4483
    Yellow Birch 3.4483

题意：给出一些树，求每种树在总数中的比例

分析：本题为了练习二叉查找树，故用BST求解，当然只用到了其插入操作。

AC代码：

#include<cstdio>
    #include<cstdlib>
    #include<cstring>
    using namespace std;
    const int maxn=1e4+10;
    typedef struct node{
    	char data[32];
    	int cnt;
    	node* lchild,*rchild;
    } *Tree,tree;
    
    Tree root;
    int n;
    
    void jisuan(Tree root){
    	if(root!=NULL){
    		jisuan(root->lchild);
    		printf("%s %.4lf\n",root->data,(double)(root->cnt)/n*100);
    		jisuan(root->rchild);
    	}
    }
    
    void InsertBST(Tree& root,char *data){
    	if(root==NULL){
    		root=(Tree)malloc(sizeof(tree));
    		strcpy(root->data,data);
    		root->lchild=NULL; root->rchild=NULL;
    		root->cnt=1;
    		return ;
    	}
    	
    	if(strcmp(data,root->data)==0){
    		root->cnt++;
    		return ;
    	}
    	
    	if(strcmp(data,root->data)>0){
    		InsertBST(root->rchild,data);
    		return ;
    	}
    	
    	if(strcmp(data,root->data)<0){
    		InsertBST(root->lchild,data);
    		return ;		
    	}
    }
    int main(){
        char s[32];
        n=0;
    	while(gets(s)){
    		InsertBST(root,s);
    		n++;
    	} 
    	
    	jisuan(root);
      return 0;	
    }