public static TreeNode buildTree(int[] inorder, int[] postorder) {
		// write your code here
		Map<Integer, Integer>map=new HashMap<>();
		int[]A=postorder, B=inorder;
		for (int i=0;i<B.length;++i)
			map.put(B[i],i);
		return bptHelper(A,0,A.length,0,A.length,map);
	}