Niu Ke (4) Rebuild the binary tree

//Title description 
// Input the result of preorder traversal and inorder traversal of a binary tree, please reconstruct the binary tree. 
// Assume that the results of the input preorder traversal and inorder traversal do not contain duplicate numbers. 
// For example, enter the preorder traversal sequence {1,2,4,7,3,5,6,8} and the inorder traversal sequence {4,7,2,1,5,3,8,6}, 
// Then rebuild the binary tree and return. 
public class test_4 { 

    public static class TreeNode { 
        int val; 
        TreeNode left; 
        TreeNode right; 

        TreeNode(int x) { 
            val = x; 
        } 
    } 

    public static TreeNode reConstructBinaryTree(int[] pre, int[] in) { 
        TreeNode tree = reConstructBinaryTree (pre, 0, pre.length - 1, in, 0, in.length - 1); 
        return tree; 
    }

    public static TreeNode reConstructBinaryTree(int[] pre, int preStartIndex, int preEndIndex, int[] in, int inStartIndex, int inEndIndex) {
        if (preStartIndex > preEndIndex || inStartIndex > inEndIndex) {
            return null;
        }
        TreeNode tree = new TreeNode(pre[preStartIndex]);

        for (int i = inStartIndex; i <= inEndIndex; i++) {
            if (pre[preStartIndex] == in[i]) {
                tree.left = reConstructBinaryTree(pre, preStartIndex + 1, preStartIndex + i - inStartIndex, in, inStartIndex, i - 1);
                tree.right = reConstructBinaryTree(pre, preStartIndex + i - inStartIndex + 1, preEndIndex, in, i + 1, inEndIndex);
            }
        }
        return tree;
    }

    public static void main(String[] args) {
        int preOrder[] = {1, 2, 4, 7, 3, 5, 6, 8};
        int inOrder[] = {4, 7, 2, 1, 5, 3, 8, 6};
        reConstructBinaryTree(preOrder, inOrder);

    }
}