给定一颗二叉搜索树，请找出其中的第k小的结点。例如， 5 / \ 3 7 /\ /\ 2 4 6 8 中，按结点数值大小顺序第三个结点的值为4。

#include "stdafx.h"
#include "stdafx.h"
#include<iostream>
#include<vector>
#include<algorithm>
#include<numeric>
#include<list>
#include<iterator>
#include<queue>
#include<stack>
#include<algorithm>
using namespace std;

struct TreeNode {
char val;
struct TreeNode *left;
struct TreeNode *right;
TreeNode(int x) :
val(x), left(NULL), right(NULL) {
}
};
class Solution {
public:
TreeNode* KthNode(TreeNode* pRoot, unsigned int k)
{
getData(pRoot);
if (k <= 0) return NULL;
if (k > qu.size()) return NULL;
for (int i = 1; i < k; i++)
{
qu.pop();
}
return qu.front();
}

queue<TreeNode*> qu;
void getData(TreeNode* T)
{
if (T == NULL) return;
else
{
getData(T->left);
qu.push(T);
getData(T->right);
}
}

//序列化二叉树，前序创建二叉树
int p = -1;
TreeNode* Deserialize(char *str) {
if (*str == NULL) return NULL; //str为空
TreeNode *T = NULL;
++p;
if (p >= strlen(str)) return NULL; //超出str的范围
if (str[p] == '#') return NULL; //str的值等于#
T = new TreeNode(str[p]);
T->left = Deserialize(str);
T->right = Deserialize(str);
return T;
}
void preOrder(TreeNode *T)
{
if (T == NULL) return;
else
{
cout << T->val << "  ";
preOrder(T->left);
preOrder(T->right);
}
}

};

int main()
{

//int num = 5;
//char *ch = new char[num];
//cout << "strlen(ch):" << strlen(ch)<<endl;
//cout << endl;

Solution so;
TreeNode *T;
int num = 5;
char *str = "532##4##76##8##";
T = so.Deserialize(str);
cout << "创建二叉树成功！"<<endl;

cout << "前序遍历二叉树：" << endl;
so.preOrder(T);
cout << endl;

TreeNode *re = so.KthNode(T,8);
cout << "result:" << re->val << endl;

//so.getData(T);
//cout << "qu 队列中的值：" << endl;
//so.print();
//cout << endl;

return 0;
}