[LeetCode]Construct Binary Tree from Preorder and Inorder Traversal

public class Solution {
    public TreeNode buildTree(int[] preorder, int[] inorder) {
        int length = preorder.length;
        if (length == 0) {
            return null;
        }
        TreeNode root = new TreeNode(preorder[0]);
        int i = 0;
        for(; i < length; i++) {
            if (inorder[i] == root.val) {
                break;
            }
        }
        root.left = buildTree(Arrays.copyOfRange(preorder, 1, 1 + i), Arrays.copyOfRange(inorder, 0, i));
        root.right = buildTree(Arrays.copyOfRange(preorder, 1 + i, length), Arrays.copyOfRange(inorder, 1 + i, length));
        return root;
    }
}