二叉搜索树的创建和判断最小祖先

public class GetBST {

    public TreeNode root;

    public GetBST(int data) {

        root = new TreeNode(data);
    }

    public static void main(String[] args) {

        /*创建根节点*/
        GetBST getBST = new GetBST(3);

        TreeNode x1 = new TreeNode(5);
        getBST.initBst(x1);

        /*创建众多子节点*/
        TreeNode x2 = new TreeNode(4);
        getBST.initBst(x2);

        TreeNode x3 = new TreeNode(0);
        getBST.initBst(x3);

        TreeNode p = new TreeNode(-2);
        getBST.initBst(p);

        TreeNode q = new TreeNode(8);
        getBST.initBst(q);

        TreeNode result = lowestCommonAncestor(getBST.root, x2, q);

        System.out.println(result.val);

    }

    /*插入搜索二叉树*/
    public void initBst(TreeNode a){

        TreeNode current;

        current = root;

        while (true) {

            if (a.val >= current.val) {

                if (current.right == null){

                    current.right = a;

                    return;
                } else {
                    current = current.right;
                }
            } else {
                if (current.left == null){

                    current.left = a;

                    return;
                } else {

                    current = current.left;
                }
            }
        }

    }

    /*搜索最小祖先*/
    public static TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) {

        if (p.val < root.val && q.val < root.val)
            return lowestCommonAncestor(root.left, p, q);

        else if (p.val > root.val && q.val > root.val)
            return lowestCommonAncestor(root.right, p, q);

        else
            return root;
    }
}

/*搜索二叉树结构*/
class TreeNode {

    int val;

    TreeNode left;

    TreeNode right;

    TreeNode(int x) {

        val = x;
    }
}