106. Construct Binary Tree from Inorder and Postorder Traversal

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

Note:

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

Subscribe to see which companies asked this question

注意要利用指针操作，前面一直用数组传参，内存超出。

/**
* Definition for a binary tree node.
* struct TreeNode {
*     int val;
*     TreeNode *left;
*     TreeNode *right;
*     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
TreeNode* buildTree(vector<int>& in, vector<int>& post) {
int len = in.size();
if(len==0) return NULL;
return build(&in[0],&post[0],len);
}
TreeNode* build(int *in,int *post,int len) {
if(len==0) return NULL;
int val=post[len-1];
int i=0;
for(;i<len&&*(in+i)!=val;++i)
{

}
int j= len-i-1;
TreeNode* root = new TreeNode(*(in+i));
root->left =build(in,post,i);
root->right=build(in+i+1,post+i,len-i-1);
return root;
}
};