LeetCode Construct Binary Tree from Inorder and Postorder Traversal

 //开始竟然忘了加return 了！！   152ms通过大的
 1 /**
 * Definition for binary tree
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:

    TreeNode *buildTree(vector<int> &inorder, int ib,int ie,vector<int> &postorder,int pb,int pe)
    {
        TreeNode *root=new  TreeNode(0);
        root->val=postorder[pe];
        
        vector<int>::iterator proot=find(inorder.begin(),inorder.end(),postorder[pe]);
        int pos=proot-inorder.begin();
        int leftLen=pos-ib;
        int rightLen=ie-pos;
        
        if(pos>ib)
            root->left=buildTree(inorder,ib,pos-1,postorder,pb,pb+leftLen-1);
        if(pos<ie)
            root->right=buildTree(inorder,pos+1,ie,postorder,pb+leftLen,pe-1);
        return root;
    }
    
    TreeNode *buildTree(vector<int> &inorder, vector<int> &postorder) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        if(inorder.size()==0)
            return NULL;
        return buildTree(inorder,0,inorder.size()-1,postorder,0,inorder.size()-1);
    }
};

 
 //小的过了，大的内存不够
 1 /**
 * Definition for binary tree
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    TreeNode *buildTree(vector<int> &inorder, vector<int> &postorder) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        if(inorder.size()==0)
        {
            return NULL;
        }
        if(inorder.size()==1)
        {
            TreeNode *root=new TreeNode(0);
            root->val=inorder[0];
            root->left=NULL;
            root->right=NULL;
            return root;
        }

        vector<int>::iterator p,q;
        TreeNode *l,*r;
        TreeNode *root=new TreeNode(0);
        int ca,cb;
        p=find(inorder.begin(),inorder.end(),postorder[postorder.size()-1]);
        ca=p-inorder.begin();
        cb=inorder.size()-(p-inorder.begin())-1;
        vector<int> va(inorder.begin(),p);
        vector<int> pa(postorder.begin(),postorder.begin()+ca);
        vector<int> vb(p+1,inorder.end());
         vector<int> pb(postorder.begin()+ca,postorder.begin()+ca+cb);
         
        root->val=*p;
        l=buildTree(va,pa);
        r=buildTree(vb,pb);
        root->left=l;
        root->right=r;
        return root;

    }
};