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) {}
* };
*/
class Solution {
public:

int getIndex(vector<int>& inorder,int inBegin,int inEnd,int value){
for(int i=inBegin;i<=inEnd;i++){
if(inorder[i]==value){
return i;
}
}
return -1;
}

TreeNode *buildTree(vector<int> &preorder,int preBegin,int preEnd,
vector<int> &inorder,int inBegin,int inEnd) {
if(preBegin>preEnd){
return NULL;
}
int index=getIndex(inorder,inBegin,inEnd,preorder[preBegin]);
TreeNode * root=new TreeNode(preorder[preBegin]);

int tmp=index-inBegin+preBegin;
root->left=buildTree(preorder,preBegin+1,tmp,inorder,inBegin,index-1);
root->right=buildTree(preorder,tmp+1,preEnd,inorder,index+1,inEnd);
return root;
}

TreeNode *buildTree(vector<int> &preorder, vector<int> &inorder) {
return buildTree(preorder,0,preorder.size()-1,inorder,0,inorder.size()-1);
}
};