Java for LeetCode 106 Construct Binary Tree from Inorder and Postorder Traversal

Construct Binary Tree from Inorder and Postorder Traversal

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

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

解题思路：

修改下上题代码解决，JAVA实现如下：

	static public TreeNode buildTree(int[] inorder, int[] postorder) {
		 return buildTree(postorder, inorder, 0, postorder.length-1, 0, inorder.length-1);  
    }  
    static public TreeNode buildTree(int[] postorder, int[] inorder, int pBegin, int pEnd, int iBegin, int iEnd){  
        if(pBegin>pEnd)  
            return null;  
        TreeNode root = new TreeNode(postorder[pEnd]);  
        int i = iBegin;  
        for(;i<iEnd;i++)
            if(inorder[i]==root.val)  
                break;  
        int lenLeft = i-iBegin;  
        root.left = buildTree(postorder, inorder, pBegin, pBegin+lenLeft-1, iBegin, i-1);  
        root.right = buildTree(postorder, inorder, pBegin+lenLeft, pEnd-1, i+1, iEnd);  
        return root;
    }