在这里插入代码片

import java.util.*;/** public class TreeNode {*   int val = 0;*   TreeNode left = null;*   TreeNode right = null;* }*/public class Solution {/*** * @param root TreeNode类 * @param sum int整型 * @return bool布尔型*/public boolean hasPathSum (TreeNode root, int sum) {// write code hereif(root==null){return false;}if(root.left==null&&root.right==null&&sum-root.val==0){return true;}return hasPathSum(root.left,sum-root.val)||hasPathSum(root.right,sum-root.val);}
}

在这里插入代码片

/*
public class ListNode {int val;ListNode next = null;ListNode(int val) {this.val = val;}
}*/
public class Solution {public ListNode Merge(ListNode list1,ListNode list2) {ListNode newhead=new ListNode(-1);ListNode cur=newhead;if(list1==null){return list2;}if(list2==null){return list1;}while(list1!=null&&list2!=null){if(list1.val<=list2.val){cur.next=list1;cur=list1;list1=list1.next;}else{cur.next=list2;cur=list2;list2=list2.next;}}if(list1!=null ){cur.next=list1;}if(list2!=null){cur.next=list2;}return newhead.next;}
}

描述
输入一棵二叉搜索树，将该二叉搜索树转换成一个排序的双向链表。

/**
public class TreeNode {int val = 0;TreeNode left = null;TreeNode right = null;public TreeNode(int val) {this.val = val;}}
*/
public class Solution {public TreeNode head=null;public TreeNode prev=null;public TreeNode Convert(TreeNode pRootOfTree) {if(pRootOfTree==null){return null;}Convert(pRootOfTree.left);if(prev==null){head=pRootOfTree;prev=pRootOfTree;}else{prev.right=pRootOfTree;pRootOfTree.left=prev;prev=pRootOfTree;}Convert(pRootOfTree.right);return head;}
}