题解 | #重建二叉树#
重建二叉树
https://www.nowcoder.com/practice/8a19cbe657394eeaac2f6ea9b0f6fcf6
//c++ 递归
/**
* Definition for binary tree
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
#include <cstddef>
#include <vector>
class Solution {
public:
TreeNode* reConstructBinaryTree(vector<int> pre,vector<int> vin) {
int m=pre.size();
int n=vin.size();
if (m==0||n==0) {
return NULL;
}
TreeNode* root=new TreeNode(pre[0]);
for(int i=0;i<n;i++){
if (pre[0]==vin[i]) {
vector<int> preleft(pre.begin()+1,pre.begin()+i+1);
vector<int> vinleft(vin.begin(),vin.begin()+i);
root->left=reConstructBinaryTree(preleft, vinleft);
vector<int> preright(pre.begin()+i+1,pre.end());
vector<int> vinright(vin.begin()+i+1,vin.end());
root->right=reConstructBinaryTree(preright, vinright);
break;
}
}
return root;
}
};
