由中序遍历和先序遍历得出二叉树，并进行中序，先序和后序的打印

#include <iostream>
#include <vector>
#include <queue>

using namespace std;

struct TreeNode {
int val;
TreeNode *left;
TreeNode *right;
TreeNode(int x) : val(x), left(NULL), right(NULL) {}
};

struct TreeNode* reConstructBinaryTree(vector<int> pre,vector<int> in)
{
int length = pre.size();
if(length == 0)
{
return NULL;
}

vector<int> pre_left, pre_right, in_left, in_right;
struct TreeNode * head = new TreeNode(pre[0]);

int index = 0;
for(int i = 0 ; i < length; i++)
{
if(pre[0] == in[i])
{
index = i;
break;
}
}

for(int i = 0 ; i < index; i++)
{
pre_left.push_back(pre[i+1]);
in_left.push_back(in[i]);
}
for(int i = index+1; i < length; i++)
{
pre_right.push_back(pre[i]);
in_right.push_back(in[i]);
}

head->left = reConstructBinaryTree(pre_left, in_left);
head->right = reConstructBinaryTree(pre_right, in_right);

return head;
};

preOrder(TreeNode * node)
{
if(node == NULL)
{
return NULL;
}
cout<<node->val<<" ";
preOrder(node->left);
preOrder(node->right);
}
inOrder(TreeNode * node)
{
if(node == NULL)
{
return NULL;
}
inOrder(node->left);
cout<<node->val<<" ";
inOrder(node->right);
}

lastOrder(TreeNode * node)
{
if(node == NULL)
{
return NULL;
}
lastOrder(node->left);
lastOrder(node->right);
cout<<node->val<<" ";
}

int main()
{
vector<int> pre = {1,2,4,7,3,5,6,8};
vector<int> in = {4,7,2,1,5,3,8,6};

struct TreeNode* tree = reConstructBinaryTree(pre, in);

cout<<"Pre print: ";
preOrder(tree);
cout<<" in print: ";
inOrder(tree);
cout<<" last print: ";
lastOrder(tree);

return 0;
}