Tree Data Structure

A tree is a type of data structure with many children for each node. The time complexity for creating a tree is O(1). And the time complexity for searching, inserting, or deleting a node which depends on the height of the tree h, so the worst time complexity is O(h).

For e.g., P is the root of the given tree.

Code Implementation:

import java.util.Scanner;

public class Tree {
    static Scanner s = new Scanner(System.in);
    public static TreeNode<Integer> takeinput(){

        System.out.println("enter next node data: ");
        int n = s.nextInt();
        TreeNode<Integer> root = new TreeNode<Integer>(n);
        System.out.println("enter the number of children for"+n);
        int children_number = s.nextInt();
        for(int i =0; i< children_number; i++){
            TreeNode<Integer> child = takeinput();
            root.children.add(child);
        }
        return root;
    }

    public static void print(TreeNode<Integer> root){
           String s = root.data + ":";
           for(int i =0; i<root.children.size(); i++){
               s = s + root.children.get(i).data + ",";
           }
        System.out.println(s);
           for(int i =0; i<root.children.size(); i++){
               print(root.children.get(i));
           }
    }
    public static TreeNode<Integer> takeinputrecursive(){
        System.out.println("enter root data");
        int rootData = s.nextInt();
        if(rootData == -1){
            return null;
        }
        TreeNode<Integer> root = new TreeNode<Integer>(rootData);
        System.out.println("enter number of children for "+rootData);
        int children_num = s.nextInt();
        while(children_num>0){
            TreeNode<Integer> child = takeinputrecursive();
            root.children.add(child);
            children_num--;
        }
        return root;
    }
    public static void main(Str[] args) {
  //    TreeNode<Integer> rootinput = takeinput();
//      print(rootinput);
      TreeNode<Integer> rootrecursive = takeinputrecursive();
      print(rootrecursive);
    }
    // that will be the input from user:

//    enter next node data:
//            4
//    enter the number of children for4
//3
//    enter next node data:
//            2
//    enter the number of children for2
//0
//    enter next node data:
//            3
//    enter the number of children for3
//1
//    enter next node data:
//            6
//    enter the number of children for6
//0
//    enter next node data:
//            5
//    enter the number of children for5
//0
    // that is the output of user
//        4:2,3,5,
//        2:
//        3:6,
//        5:
//        6:
}

Here the implementation of code is simple or recursive.