本題為劍指offer面試題63

• 熱度指數：40095  時間限制：1秒  空間限制：32768K

package go.jacob.day613;

import java.util.Stack;

/*
 * 二叉樹中序遍歷的應用
 * 二叉搜尋樹的中序遍歷：從小到大輸出節點
 */
public class Demo1 {
	TreeNode KthNode(TreeNode pRoot, int k) {
		if (pRoot == null || k <= 0)
			return null;
		int index = 0;
		TreeNode kthNode = null;
		TreeNode node = pRoot;
		Stack<TreeNode> stack = new Stack<TreeNode>();
		while (node != null || !stack.isEmpty()) {
			if (node != null) {
				stack.push(node);
				node = node.left;
			} else {
				node = stack.pop();
				index++;
				//當遍歷到第k個節點時，跳出迴圈
				if (index == k) {
					kthNode = node;
					break;
				}
				node = node.right;
			}
		}
		return kthNode;
	}
}

class TreeNode {
	int val = 0;
	TreeNode left = null;
	TreeNode right = null;

	public TreeNode(int val) {
		this.val = val;

	}

}