题目描述 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,
/**
* 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> in) {
int len=in.size();
if(len==0)return NULL;
vector<int>left_pre,right_pre;
vector<int>left_in,right_in;
TreeNode* head=new TreeNode(pre[0]);
int index=0;
for(int i=0;i<len;i++)
{
if(in[i]==pre[0])
{
index=i;
break;
}
}
for(int i=0;i<index;i++)
{
left_pre.push_back(pre[i+1]);
left_in.push_back(in[i]);
}
for(int i=index+1;i<len;i++)
{
right_pre.push_back(pre[i]);
right_in.push_back(in[i]);
}
head->left=reConstructBinaryTree(left_pre,left_in);
head->right=reConstructBinaryTree(right_pre,right_in);
return head;
}
};