码迷,mamicode.com
首页 > 其他好文 > 详细

Construct Binary Tree from Preorder and Inorder Traversal

时间:2014-08-17 16:54:02      阅读:160      评论:0      收藏:0      [点我收藏+]

标签:style   blog   color   io   strong   ar   art   div   

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

Note:

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

思路:利用先序遍历提供的根节点信息,在中序遍历中找到根节点,进而将序列分成{左子树,根,右子树},递归求解左右子树即可。

 1 class Solution {
 2 public:
 3     TreeNode *buildTree( vector<int> &preorder, vector<int> &inorder ) {
 4         if( preorder.empty() || preorder.size() != inorder.size() ) { return 0; }
 5         return BuildSub( preorder, 0, preorder.size()-1, inorder, 0, inorder.size()-1 );
 6     }
 7 private:
 8     TreeNode *BuildSub( vector<int> &preorder, int preStart, int preEnd, vector<int> &inorder, int inStart, int inEnd ) {
 9         if( inStart > inEnd ) { return 0; }
10         int index = 0;
11         while( inorder[inStart+index] != preorder[preStart] ) { ++index; }
12         TreeNode *treeNode = new TreeNode( preorder[preStart] );
13         treeNode->left = BuildSub( preorder, preStart+1, preStart+index, inorder, inStart, inStart+index-1 );
14         treeNode->right = BuildSub( preorder, preStart+index+1, preEnd, inorder, inStart+index+1, inEnd );
15         return treeNode;
16     }
17 };

 

Construct Binary Tree from Preorder and Inorder Traversal,布布扣,bubuko.com

Construct Binary Tree from Preorder and Inorder Traversal

标签:style   blog   color   io   strong   ar   art   div   

原文地址:http://www.cnblogs.com/moderate-fish/p/3917864.html

(0)
(0)
   
举报
评论 一句话评论(0
登录后才能评论!
© 2014 mamicode.com 版权所有  联系我们:gaon5@hotmail.com
迷上了代码!