Java binary tree sort and traversal file display text format file tree

  • 2020-04-01 04:25:10
  • OfStack

Java binary tree sorting algorithm
The description of sort binary tree is also a recursive description, so the construction of sort binary tree is also recursive:
Three characteristics of sort binary tree:
1: the value of all the left children of the current node is less than the value of the current node;
2: the value of all right children of the current node is greater than the value of the current node;
3: the child node also satisfies the above two points


package test.sort; 
 
public class BinaryNode { 
 private int value;//current value 
 private BinaryNode lChild;//left child 
 private BinaryNode rChild;//right child 
  
 public BinaryNode(int value, BinaryNode l, BinaryNode r){ 
  this.value = value; 
  this.lChild = l; 
  this.rChild = r; 
 } 
  
 public BinaryNode getLChild() { 
  return lChild; 
 } 
 public void setLChild(BinaryNode child) { 
  lChild = child; 
 } 
 public BinaryNode getRChild() { 
  return rChild; 
 } 
 public void setRChild(BinaryNode child) { 
  rChild = child; 
 } 
 public int getValue() { 
  return value; 
 } 
 public void setValue(int value) { 
  this.value = value; 
 } 
  
 //iterate all node. 
 public static void iterate(BinaryNode root){ 
  if(root.lChild!=null){ 
   iterate(root.getLChild()); 
  } 
  System.out.print(root.getValue() + " "); 
  if(root.rChild!=null){ 
   iterate(root.getRChild()); 
  } 
 } 
  
  
 public void addChild(int n){ 
  if(n<value){ 
   if(lChild!=null){ 
    lChild.addChild(n); 
   } 
   else{ 
    lChild = new BinaryNode(n, null, null); 
   } 
  } 
  else{ 
   if(rChild!=null){ 
    rChild.addChild(n); 
   } 
   else{ 
    rChild = new BinaryNode(n, null, null); 
   } 
  } 
 } 
  
 //test case. 
 public static void main(String[] args){ 
  System.out.println(); 
  int[] arr = new int[]{23,54,1,65,9,3,100}; 
  BinaryNode root = new BinaryNode(arr[0], null, null); 
  for(int i=1; i<arr.length; i++){ 
   root.addChild(arr[i]); 
  } 
  BinaryNode.iterate(root); 
 } 
} 

The Java traversal file displays a tree of files in text format
Write a code in Java to change the file tree, print out the structure, similar to the CMD input command tree results.
I thought it was easy, but when I did it, I realized it was hard. If you are interested, you can try it.


package test.io;
//Look for on the net, hear or old word bamboo original creation. The code was simple, but I had a lot of trouble digesting it
import java.util.ArrayList;
import java.util.List;
public class Folder {
 public Folder(String title) {
  this.title = title;
 }
 private String title;
 private List<Folder> children = new ArrayList<Folder>();
 public void addChild(Folder f) {
  children.add(f);
 }
 public List<Folder> getChildren() {
  return children;
 }
 public void setChildren(List<Folder> children) {
  this.children = children;
 }
 public String getTitle() {
  return title;
 }
 public void setTitle(String title) {
  this.title = title;
 }
 public String toString(String lftStr, String append) {
  StringBuilder b = new StringBuilder();
  b.append(append + title);
  b.append("/n");
  if (children.size() > 0) {
   for (int i = 0; i < children.size() - 1; i++) {
    b.append(lftStr+ children.get(i).toString(lftStr + " │  ", 
" ├ -"));
   }
   b.append(lftStr+ children.get(children.size() - 1).toString(lftStr + 
" "," └ -"));
  }
  return b.toString();
 }
 public static void main(String[] args) {
  Folder root = new Folder(" Menu list ");
  Folder f1 = new Folder(" The start menu ");
  root.addChild(f1);
  Folder f1_1 = new Folder(" The program ");
  f1.addChild(f1_1);
  Folder f1_1_1 = new Folder(" The attachment ");
  f1_1.addChild(f1_1_1);
  Folder f1_1_1_1 = new Folder(" entertainment ");
  f1_1_1.addChild(f1_1_1_1);
  Folder f1_1_1_2 = new Folder(" entertainment 2");
  f1_1_1.addChild(f1_1_1_2);
  Folder f1_2 = new Folder(" Auxiliary tool ");
  f1.addChild(f1_2);
  System.out.println(root.toString(" ", "$"));
 }
}
//**************************************
//I modified it after digestion. Printable file structure
import java.io.*; 
public class DocTree { 
 File root = null; 
  
 public DocTree(File f){ 
  this.root = f; 
 }
  
 public static void main(String[] args){ 
  File root = new File("c://test"); 
  DocTree tree = new DocTree(root); 
  System.out.println(tree.toString(" ", "")); 
 } 
  
 public String toString(String leftStr, String append){ 
  StringBuilder b = new StringBuilder(); 
  b.append(append + root.getName()); 
  b.append("/n");
  if(!root.isFile()&&root.listFiles().length!=0){ 
   File[] files = root.listFiles(); 
   DocTree[] docTrees = new DocTree[files.length]; 
   for(int i=0; i<docTrees.length; i++){ 
    docTrees[i] = new DocTree(files[i]); 
   } 
   for (int i=0; i<files.length-1; i++){ 
    b.append(leftStr + docTrees[i].toString(leftStr+" │ ", " ├ ")); 
   } 
   b.append(leftStr + docTrees[docTrees.length-1].toString(leftStr + " ", " └ ")); 
  } 
  return b.toString(); 
 }
}
//*****************************************
//And I still don't think it's convenient to understand, and in a few days I might forget,
//Or to write their own, although the idea copy, but I think their understanding is very convenient.
//Take notes,
import java.io.*;
public class Tree {
 File root = null;
 public Tree(File f){
  this.root = f;
 }
 
 
 
 public void showTree(File root, String childLeftStr, String junction){
  //Print node information
  System.out.println(junction + root.getName());
  //If there are children and the number of children is not zero
  if(!root.isFile()&&root.listFiles().length!=0){
   File[] files = root.listFiles();
   //Construct child node
   Tree[] children = new Tree[files.length];
   for(int i=0; i<files.length; i++){
    children[i] = new Tree(files[i]);
   }
   //Print child node
   for(int i=0; i<children.length-1; i++){
    //For all the child nodes, print out the structure information on the left,
    System.out.print(childLeftStr);
    //Recursively call showTree, notice that the parameters change and the depth of the file increases
 So will the structural information of its children 
    //Add, if not the last child, then the structure of the information to add "information,".
    showTree(children[i].root,childLeftStr+" │ ", " ├ ");
   }
   //The last child needs special treatment
   //Print structure information
   System.out.print(childLeftStr);
   //If it is the last child, the structure information needs to be added "".
   //Node shapes have been adjusted to " └ "
   showTree(children[files.length-1].root, childLeftStr+" "," └ ");
  }
 }
 public static void main(String[] args) {
  File f = new File("C://test");
  Tree t = new Tree(f);
  t.showTree(f,"", "");
 }
}


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