java 면접문제 - 이미 알고 있는 선순과 중순 두루

class Node {
	public int data;
	public Node left;
	public Node right;
	
	public Node() {
	}
	public Node(int data) {
		this.data = data;
		this.left=null;
		this.left=null;
	}
}
public class BinaryTree {

	private Node root;

	public BinaryTree() {
		root=null;
	}
	// 
	public void postOrder(Node localRoot){
		if(localRoot!=null){
			postOrder(localRoot.left);
			postOrder(localRoot.right);
			System.out.print(localRoot.data+" ");
		}
	}
	public void postOrder(){
		this.postOrder(this.root);
	}
	public void initTree(int[] preOrder,int []inOrder){
		this.root=this.initTree(preOrder, 0,preOrder.length-1,inOrder,0,inOrder.length);
	}

	public Node initTree(int[] preOrder, int start1, int end1, int[] inOrder, int start2,
			int end2) {
		if(start1>end1 || start2>end2){
			return null;
		}
		int rootData=preOrder[start1];
		Node head=new Node(rootData);
		
		// 
		int rootIndex=findIndexInArray(inOrder,rootData,start2,end2);
		int offSet=rootIndex-start2-1;// 
		// 
		head.left=initTree(preOrder,start1+1,start1+1+offSet,inOrder,start2,start2+offSet);
		// 
		head.right=initTree(preOrder,start1+2+offSet,end1,inOrder,rootIndex+1,end2);
		
		return head;
	}

	public int findIndexInArray(int[] inOrder, int rootData, int begin,
			int end) {
		for (int i = begin; i <= end; i++) {
			if(inOrder[i]==rootData){
				return i;
			}
		}
		return -1;
	}
	
	public static void main(String[] args) {
		BinaryTree bt=new BinaryTree();
		int[]preOrder={1,2,4,8,9,5,10,3,6,7};
		int[]inOrder={8,4,9,2,10,5,1,6,3,7};
		bt.initTree(preOrder, inOrder);
		System.out.println(" ：");
		bt.postOrder();
	}
}