Leetcode-Construct binary tree from preorder and inorder Traversal

Given preorder and inorder traversal of a tree, construct the binary tree.

Note:
You may assume that duplicates do not exist in the tree.

/** * Definition for binary tree * struct TreeNode { *     int val; *     TreeNode *left; *     TreeNode *right; *     TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */struct TreeNode{int val;TreeNode *left;TreeNode *right;TreeNode(int x) : val(x), left(NULL), right(NULL) {}};class Solution {public:    TreeNode *buildTree(std::vector<int> &preorder, std::vector<int> &inorder) {return buildBinTree(preorder,0,preorder.size()-1,inorder,0,inorder.size()-1);    }private:TreeNode *buildBinTree(std::vector<int> &preorder,int preStart,int preEnd,std::vector<int> &inorder,int inStart,int inEnd){if(preStart > preEnd || inStart > inEnd) return NULL;TreeNode *root = new TreeNode(preorder[preStart]);int rootIndex = 0;for (int i = inStart; i <= inEnd; i++){if(inorder[i] == root->val){rootIndex = i;break;}}int len = rootIndex - inStart;root->left = buildBinTree(preorder,preStart+1,preStart+len,inorder,inStart,rootIndex-1);root->right = buildBinTree(preorder,preStart+len+1,preEnd,inorder,rootIndex+1,inEnd);return root;}};

Leetcode-Construct binary tree from preorder and inorder Traversal