树--计算树的深度

package com.Tree;

import java.util.Stack;
/*
 * 计算二叉树深度方法（递归 和 非递归）
 */
public class Depth {
	//recursive depth()
	public int recDepth(BTNode p) {
		int ldepth, rdepth;
		
		if (p == null)
			return 0;
		else {
			ldepth = recDepth(p.left);
			rdepth = recDepth(p.right);
			return Math.max(ldepth, rdepth) + 1;
		}
	}
	//non-recursive depth();
	//中序非递归
	public int nonRecDepth(BTNode p) {
		Stack<BTNode> stack1 = new Stack<BTNode>();
		Stack<Integer> stack2 = new Stack<Integer>();
		int curdep, maxdep = 0;
		
		curdep = 1;
		while (p != null || stack1.empty() == false) {
			while (p != null) {
				stack1.push(p);
				stack2.push(curdep);
				p = p.left;
				curdep++;
			}
			p = stack1.pop();
			curdep = stack2.pop();
			if (p.left == null && p.right == null)
				maxdep = Math.max(curdep, maxdep);
			p = p.right;
			curdep++;
		}
		return maxdep;
	}
	//前序非递归
	public int prenonRecDepth(BTNode p) {
		Stack<BTNode> stack1 = new Stack<BTNode>();
		Stack<Integer> stack2 = new Stack<Integer>();
		int curdep, maxdep = 0;
		
		curdep = 1;
		while (p != null || stack1.empty() == false) {
			while (p != null) {
				if (p.left == null && p.right == null)
					maxdep = Math.max(curdep, maxdep);
				stack1.push(p);
				stack2.push(curdep);
				p = p.left;
				curdep++;
			}
			p = stack1.pop();
			curdep = stack2.pop();
			
			p = p.right;
			curdep++;
		}
		return maxdep;
	}
	
	
}