老人家的舊書房

囧！

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import java.io.*;
import java.util.*;

class node{
 int key;
 node left;
 node right;
 node(int k){
  key = k;
  left = null;
  right = null;
 }
}

class BST{
 node root;
 BST(File f)throws FileNotFoundException{
 build(f); 
 }
 void build(File f)throws FileNotFoundException{
  Scanner sr = new Scanner(f);
  root = new node(sr.nextInt());
  while(sr.hasNextInt()){
   int k = sr.nextInt();
   node p = null, r = root;
   while(r!=null){
    p = r;
    r = k<r.key? r.left:r.right;
   }
   if(k<p.key)
    p.left = new node(k);
   else
    p.right = new node(k);
   //k<p.key? p.left=new node(k):p.right=new node(k);
  }
  sr.close();
 }
 public void infixTraverse(node t){
  if(t==null)
   return;
  infixTraverse(t.left);
  System.out.println(t.key+" ");
  infixTraverse(t.right);
 }
 public boolean search(int k){
  node r = root;
  int count = 0;
  boolean found = false;
  while(!found && r!=null){
   count++;
   if(k==r.key){
    found = true;
   }else if(k<r.key){
    r = r.left;
   }else{
    r = r.right;
   }
   System.out.print(count+" ");
   }
   return found;
 }
}
 public class BinarySearchTree{
  public static void main(String[] alio)throws FileNotFoundException{
   File f = new File("BinarySearchTreeText.txt");
   BST bt = new BST(f);
   bt.infixTraverse(bt.root);
   System.out.println();
   System.out.println(bt.search(32/*檔案中之資料搜尋*/));
   System.out.println(bt.search(3));
  }
 }
 

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話說上面這台有支援雙打喔XD