//输入某二叉树的前序遍历和中序遍历的结果,请重建出该二叉树。假设输入的前序遍历和中序遍历的结果中都不含重复的数字。例如输入前序遍历序列{1,2,4,7,3,5,6,8}和中序遍历序列{4,7,2,1,5,3,8,6},则重建二叉树并返回。
/**
* 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* reConstructBinaryTree(vector<int> pre,vector<int> vin)
{
if (pre.empty())
return NULL;
TreeNode *head = new TreeNode(pre[0]);
vector<int> ::iterator pos = find(vin.begin(), vin.end(), pre[0]);
vector<int> vinleft (vin.begin(), pos);
vector<int> vinright(pos + 1, vin.end());
vector<int> preleft(pre.begin()+1, pre.begin()+vinleft.size() +1);
vector<int> preright(pre.begin()+vinleft.size() +1, pre.end());
head->left = reConstructBinaryTree(preleft, vinleft);
head->right = reConstructBinaryTree(preright, vinright);
return head;
}
};