题解 | #插入二叉搜索树#

import java.util.*;

/*
 * public class TreeNode {
 *   int val = 0;
 *   TreeNode left = null;
 *   TreeNode right = null;
 *   public TreeNode(int val) {
 *     this.val = val;
 *   }
 * }
 */

public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param root TreeNode类 
     * @param val int整型 
     * @return TreeNode类
     */
    public TreeNode insertToBST (TreeNode root, int val) {
        // write code here
        process(root, val);
        return root;
    }
    
    public void process(TreeNode node, int val) {
        if (node.val > val) {
            if (null == node.left) {
                TreeNode tmpNode = new TreeNode(val);
                node.left = tmpNode;
            }
            else {
                process(node.left, val);
            }
        }
        else {
            if (null == node.right) {
                TreeNode tmpNode = new TreeNode(val);
                node.right = tmpNode;
            }
            else {
                process(node.right, val);
            }
        }
    }
}