Create Construct Binary Tree from Inorder and Postorder Traversal 

The last int in postorder array is the value of root, then find the root value in inorder array, depart inorder array by root value, then left side is left subtree, right side is right subtree.
Depart the postorder array without the root value by the number of the left side and right side of the inorder array, the the left side is postorder array of the left subtree, and the right side is the postorder array of the right subtree.
Do the above recursively.