根据前序 中序 后序 构建二叉树

//Construct Binary Tree from Inorder and Postorder #include <iostream>#include <vector>using namespace std;struct TreeNode{    int val;    TreeNode *left, *right;    TreeNode(int data): val(data), left(NULL), right(NULL){    }};class Solution{    public:        //根据中序和后序遍历 构建二叉树        TreeNode *buildTree(vector<int> &inorder, vector<int> &postorder){            return buildTree(inorder, 0, inorder.size() - 1, postorder, 0, postorder.size() - 1);        }        TreeNode *buildTree(vector<int> &inorder, int iLeft, int iRight, vector<int> &postorder, int pLeft, int pRight) {            if(iLeft > iRight || pLeft > pRight){                return NULL;            }            TreeNode *cur = new TreeNode (postorder[pRight]);            int i = 0;            for(i = iLeft; i < inorder.size(); ++i){                if(inorder[i] == cur->val){                    break;                }            }            cur->left = buildTree(inorder, iLeft, i - 1, postorder, pLeft, pLeft + i - iLeft - 1);            cur->right = buildTree(inorder, i + 1, iRight, postorder, pLeft + i - iLeft, pRight - 1);            return cur;        }          //根据前序和中序遍历 构建二叉树        TreeNode *buildTree2(vector<int> &preorder, vector<int> &inorder){            return buildTree2(preorder, 0, preorder.size() - 1, inorder, 0, inorder.size() - 1);        }        TreeNode *buildTree2(vector<int> &preorder, int iLeft, int iRight, vector<int> &inorder, int pLeft, int pRight) {            if(iLeft > iRight || pLeft > pRight){                return NULL;            }            TreeNode *cur = new TreeNode(preorder[iLeft]);            int i;            //for(i = 0; i < inorder.size(); ++i){            for(i = pLeft; i <= pRight; ++i){                       if(inorder[i] == cur->val){                    break;                }            }            cur->left = buildTree2(preorder, iLeft + 1, iLeft +  i - pLeft , inorder, pLeft , i - 1);            cur->right = buildTree2(preorder, iLeft + i - pLeft + 1, iRight, inorder, i + 1, pRight);            return cur;    }};//前序遍历输出void PreorderDisplay(TreeNode *root){    if(root == NULL){        return ;    }    else    {        cout << root->val <<" ";        PreorderDisplay(root->left);         PreorderDisplay(root->right);    }}//后序遍历输出void PostorderDisplay(TreeNode *root){    if(root == NULL){        return ;    }    else    {        PostorderDisplay(root->left);        PostorderDisplay(root->right);        cout << root->val << " ";    }}int main(){    Solution s;    TreeNode *res, *res1;    vector<int> inorder = {11,4,5,13,8,9};    vector<int> preorder = {5,4,11,8,13,9};    vector<int> postorder = {11,4,13,9,8,5};//  res = s.buildTree(inorder, postorder);//  PreorderDisplay(res);//  cout << endl;    cout << 2 << endl;    res1 = s.buildTree2(preorder, inorder);    cout << 2 << endl;    //cout << res1->val << endl;     PostorderDisplay(res1);    system("pause");    return 0;}