Construct Binary Tree from inorder and Postorder traversal

Given Inorder and Postorder traversal of a tree, construct the binary tree.

Constructs a binary tree based on the middle sequence (left root right) and post-order traversal of the tree

Reference: http://www.cnblogs.com/remlostime/archive/2012/10/29/2744738.html

The last element of the post-order traversal is the root node, which divides the middle sequence traversal array into two arrays through the root node, which is a collection of Saozi right sub-tree nodes, which are recursively called

Use the subscript here to save space

1  Public classSolution {2      PublicTreeNode Buildtree (int[] inorder,int[] postorder) {3 TreeNode Root;4         if(0 = =inorder.length)5             return NULL;6         Else 7             returnCreatetree (inorder, postorder, 0, inorder.length-1, 0, Postorder.length-1);8         9     }Ten     PrivateTreeNode Createtree (int[]inorder,int[] Postorder,intInstart,intInend,intPoststart,intpostend) { One         if(Instart >inend) A             return NULL; -         intValue_root = Postorder[postend];//the value of the root node -         intindex = 0;//The index value of the root node in the middle sequence traversal the          for(inti = Instart; I <= inend; i++) {//find the index value of the root node in the final traverse -             if(Postorder[postend] = =Inorder[i]) { -index =i; -                  Break; +             } -         } +         intLength_lefttree = Index-instart;//Length of Zuozi ATreeNode lefttreeroot = Createtree (inorder, Postorder, Instart, Index-1, Poststart, Poststart + length_lefttree-1);  atTreeNode righttreeroot = Createtree (inorder, Postorder, index + 1, inend, Poststart + length_lefttree, postEnd-1); -          -TreeNode root =NewTreeNode (value_root); -          -Root.left =Lefttreeroot; -Root.right =Righttreeroot; in          -         returnRoot; to     } +}

Construct Binary Tree from inorder and Postorder traversal