## 深度优先搜索

| \# | 题名 | 题解 | 通过率 | 难度 | 出现频率   |
|------|----------------------|-----|--------|----|--------|
|546|[移除盒子](https://leetcode-cn.com/problems/remove-boxes)   |[8](https://leetcode-cn.com/problems/remove-boxes/solution)|48.7%|困难|79.34%|
|679|[24 点游戏](https://leetcode-cn.com/problems/24-game)   |[14](https://leetcode-cn.com/problems/24-game/solution)|40.6%|困难|65.38%|
|488|[祖玛游戏](https://leetcode-cn.com/problems/zuma-game)   |[8](https://leetcode-cn.com/problems/zuma-game/solution)|40.4%|困难|53.62%|
|1203|[项目管理](https://leetcode-cn.com/problems/sort-items-by-groups-respecting-dependencies)   |[5](https://leetcode-cn.com/problems/sort-items-by-groups-respecting-dependencies/solution)|32.0%|困难|49.92%|
|834|[树中距离之和](https://leetcode-cn.com/problems/sum-of-distances-in-tree)   |[7](https://leetcode-cn.com/problems/sum-of-distances-in-tree/solution)|30.7%|困难|49.5%|
|1236|[Web Crawler](https://leetcode-cn.com/problems/web-crawler)   |[4](https://leetcode-cn.com/problems/web-crawler/solution)|52.5%|中等|46.1%|
|394|[字符串解码](https://leetcode-cn.com/problems/decode-string)   |[70](https://leetcode-cn.com/problems/decode-string/solution)|47.4%|中等|43.91%|
|753|[破解保险箱](https://leetcode-cn.com/problems/cracking-the-safe)   |[4](https://leetcode-cn.com/problems/cracking-the-safe/solution)|53.4%|困难|43.23%|
|778|[水位上升的泳池中游泳](https://leetcode-cn.com/problems/swim-in-rising-water)   |[14](https://leetcode-cn.com/problems/swim-in-rising-water/solution)|45.3%|困难|41.54%|
|711|[不同岛屿的数量 II](https://leetcode-cn.com/problems/number-of-distinct-islands-ii)   |[6](https://leetcode-cn.com/problems/number-of-distinct-islands-ii/solution)|52.6%|困难|40.01%|
|124|[二叉树中的最大路径和](https://leetcode-cn.com/problems/binary-tree-maximum-path-sum)   |[71](https://leetcode-cn.com/problems/binary-tree-maximum-path-sum/solution)|38.4%|困难|39.36%|
|839|[相似字符串组](https://leetcode-cn.com/problems/similar-string-groups)   |[16](https://leetcode-cn.com/problems/similar-string-groups/solution)|28.9%|困难|39.06%|
|329|[矩阵中的最长递增路径](https://leetcode-cn.com/problems/longest-increasing-path-in-a-matrix)   |[19](https://leetcode-cn.com/problems/longest-increasing-path-in-a-matrix/solution)|38.9%|困难|37.94%|
|200|[岛屿数量](https://leetcode-cn.com/problems/number-of-islands)   |[125](https://leetcode-cn.com/problems/number-of-islands/solution)|46.3%|中等|36.08%|
|199|[二叉树的右视图](https://leetcode-cn.com/problems/binary-tree-right-side-view)   |[83](https://leetcode-cn.com/problems/binary-tree-right-side-view/solution)|62.2%|中等|35.65%|
|364|[加权嵌套序列和 II](https://leetcode-cn.com/problems/nested-list-weight-sum-ii)   |[10](https://leetcode-cn.com/problems/nested-list-weight-sum-ii/solution)|66.5%|中等|35.26%|
|1192|[查找集群内的「关键连接」](https://leetcode-cn.com/problems/critical-connections-in-a-network)   |[7](https://leetcode-cn.com/problems/critical-connections-in-a-network/solution)|31.8%|困难|34.72%|
|491|[递增子序列](https://leetcode-cn.com/problems/increasing-subsequences)   |[15](https://leetcode-cn.com/problems/increasing-subsequences/solution)|43.9%|中等|33.87%|
|928|[尽量减少恶意软件的传播 II](https://leetcode-cn.com/problems/minimize-malware-spread-ii)   |[7](https://leetcode-cn.com/problems/minimize-malware-spread-ii/solution)|37.9%|困难|32.98%|
|924|[尽量减少恶意软件的传播](https://leetcode-cn.com/problems/minimize-malware-spread)   |[11](https://leetcode-cn.com/problems/minimize-malware-spread/solution)|41.1%|困难|32.98%|
|664|[奇怪的打印机](https://leetcode-cn.com/problems/strange-printer)   |[9](https://leetcode-cn.com/problems/strange-printer/solution)|40.3%|困难|32.98%|
|301|[删除无效的括号](https://leetcode-cn.com/problems/remove-invalid-parentheses)   |[15](https://leetcode-cn.com/problems/remove-invalid-parentheses/solution)|44.5%|困难|32.67%|
|695|[岛屿的最大面积](https://leetcode-cn.com/problems/max-area-of-island)   |[46](https://leetcode-cn.com/problems/max-area-of-island/solution)|58.7%|中等|32.58%|
|547|[朋友圈](https://leetcode-cn.com/problems/friend-circles)   |[75](https://leetcode-cn.com/problems/friend-circles/solution)|53.9%|中等|29.35%|
|743|[网络延迟时间](https://leetcode-cn.com/problems/network-delay-time)   |[24](https://leetcode-cn.com/problems/network-delay-time/solution)|44.7%|中等|27.01%|
|105|[从前序与中序遍历序列构造二叉树](https://leetcode-cn.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal)   |[79](https://leetcode-cn.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal/solution)|63.2%|中等|26.17%|
|104|[二叉树的最大深度](https://leetcode-cn.com/problems/maximum-depth-of-binary-tree)   |[198](https://leetcode-cn.com/problems/maximum-depth-of-binary-tree/solution)|71.5%|简单|24.52%|
|1123|[最深叶节点的最近公共祖先](https://leetcode-cn.com/problems/lowest-common-ancestor-of-deepest-leaves)   |[17](https://leetcode-cn.com/problems/lowest-common-ancestor-of-deepest-leaves/solution)|61.6%|中等|24.28%|
|721|[账户合并](https://leetcode-cn.com/problems/accounts-merge)   |[15](https://leetcode-cn.com/problems/accounts-merge/solution)|30.2%|中等|23.58%|
|505|[迷宫 II](https://leetcode-cn.com/problems/the-maze-ii)   |[10](https://leetcode-cn.com/problems/the-maze-ii/solution)|42.0%|中等|23.58%|
|101|[对称二叉树](https://leetcode-cn.com/problems/symmetric-tree)   |[153](https://leetcode-cn.com/problems/symmetric-tree/solution)|49.2%|简单|23.48%|
|114|[二叉树展开为链表](https://leetcode-cn.com/problems/flatten-binary-tree-to-linked-list)   |[80](https://leetcode-cn.com/problems/flatten-binary-tree-to-linked-list/solution)|66.5%|中等|23.26%|
|515|[在每个树行中找最大值](https://leetcode-cn.com/problems/find-largest-value-in-each-tree-row)   |[26](https://leetcode-cn.com/problems/find-largest-value-in-each-tree-row/solution)|56.9%|中等|23%|
|863|[二叉树中所有距离为 K 的结点](https://leetcode-cn.com/problems/all-nodes-distance-k-in-binary-tree)   |[26](https://leetcode-cn.com/problems/all-nodes-distance-k-in-binary-tree/solution)|44.6%|中等|22.58%|
|110|[平衡二叉树](https://leetcode-cn.com/problems/balanced-binary-tree)   |[99](https://leetcode-cn.com/problems/balanced-binary-tree/solution)|49.4%|简单|22.24%|
|542|[01 矩阵](https://leetcode-cn.com/problems/01-matrix)   |[27](https://leetcode-cn.com/problems/01-matrix/solution)|37.1%|中等|21.95%|
|514|[自由之路](https://leetcode-cn.com/problems/freedom-trail)   |[12](https://leetcode-cn.com/problems/freedom-trail/solution)|37.5%|困难|21.17%|
|106|[从中序与后序遍历序列构造二叉树](https://leetcode-cn.com/problems/construct-binary-tree-from-inorder-and-postorder-traversal)   |[54](https://leetcode-cn.com/problems/construct-binary-tree-from-inorder-and-postorder-traversal/solution)|65.8%|中等|20.96%|
|1026|[节点与其祖先之间的最大差值](https://leetcode-cn.com/problems/maximum-difference-between-node-and-ancestor)   |[12](https://leetcode-cn.com/problems/maximum-difference-between-node-and-ancestor/solution)|55.3%|中等|20.81%|
|980|[不同路径 III](https://leetcode-cn.com/problems/unique-paths-iii)   |[13](https://leetcode-cn.com/problems/unique-paths-iii/solution)|68.7%|困难|20.25%|
|494|[目标和](https://leetcode-cn.com/problems/target-sum)   |[33](https://leetcode-cn.com/problems/target-sum/solution)|42.3%|中等|19.78%|
|108|[将有序数组转换为二叉搜索树](https://leetcode-cn.com/problems/convert-sorted-array-to-binary-search-tree)   |[97](https://leetcode-cn.com/problems/convert-sorted-array-to-binary-search-tree/solution)|68.1%|简单|19.59%|
|207|[课程表](https://leetcode-cn.com/problems/course-schedule)   |[57](https://leetcode-cn.com/problems/course-schedule/solution)|48.5%|中等|18.71%|
|968|[监控二叉树](https://leetcode-cn.com/problems/binary-tree-cameras)   |[12](https://leetcode-cn.com/problems/binary-tree-cameras/solution)|35.2%|困难|18.12%|
|112|[路径总和](https://leetcode-cn.com/problems/path-sum)   |[100](https://leetcode-cn.com/problems/path-sum/solution)|48.4%|简单|17.99%|
|988|[从叶结点开始的最小字符串](https://leetcode-cn.com/problems/smallest-string-starting-from-leaf)   |[17](https://leetcode-cn.com/problems/smallest-string-starting-from-leaf/solution)|41.9%|中等|17.8%|
|499|[迷宫 III](https://leetcode-cn.com/problems/the-maze-iii)   |[11](https://leetcode-cn.com/problems/the-maze-iii/solution)|29.1%|困难|17.74%|
|133|[克隆图](https://leetcode-cn.com/problems/clone-graph)   |[47](https://leetcode-cn.com/problems/clone-graph/solution)|47.9%|中等|17.12%|
|130|[被围绕的区域](https://leetcode-cn.com/problems/surrounded-regions)   |[59](https://leetcode-cn.com/problems/surrounded-regions/solution)|38.6%|中等|17.05%|
|337|[打家劫舍 III](https://leetcode-cn.com/problems/house-robber-iii)   |[52](https://leetcode-cn.com/problems/house-robber-iii/solution)|54.9%|中等|16.83%|
|99|[恢复二叉搜索树](https://leetcode-cn.com/problems/recover-binary-search-tree)   |[44](https://leetcode-cn.com/problems/recover-binary-search-tree/solution)|54.1%|困难|16.65%|
|109|[有序链表转换二叉搜索树](https://leetcode-cn.com/problems/convert-sorted-list-to-binary-search-tree)   |[42](https://leetcode-cn.com/problems/convert-sorted-list-to-binary-search-tree/solution)|69.5%|中等|16.61%|
|1245|[树的直径](https://leetcode-cn.com/problems/tree-diameter)   |[7](https://leetcode-cn.com/problems/tree-diameter/solution)|39.6%|中等|16.58%|
|439|[三元表达式解析器](https://leetcode-cn.com/problems/ternary-expression-parser)   |[12](https://leetcode-cn.com/problems/ternary-expression-parser/solution)|55.6%|中等|16.26%|
|934|[最短的桥](https://leetcode-cn.com/problems/shortest-bridge)   |[20](https://leetcode-cn.com/problems/shortest-bridge/solution)|42.6%|中等|16.01%|
|559|[N叉树的最大深度](https://leetcode-cn.com/problems/maximum-depth-of-n-ary-tree)   |[44](https://leetcode-cn.com/problems/maximum-depth-of-n-ary-tree/solution)|67.5%|简单|14.96%|
|332|[重新安排行程](https://leetcode-cn.com/problems/reconstruct-itinerary)   |[15](https://leetcode-cn.com/problems/reconstruct-itinerary/solution)|34.0%|中等|14.96%|
|111|[二叉树的最小深度](https://leetcode-cn.com/problems/minimum-depth-of-binary-tree)   |[110](https://leetcode-cn.com/problems/minimum-depth-of-binary-tree/solution)|40.8%|简单|14.85%|
|694|[不同岛屿的数量](https://leetcode-cn.com/problems/number-of-distinct-islands)   |[16](https://leetcode-cn.com/problems/number-of-distinct-islands/solution)|42.2%|中等|14.76%|
|638|[大礼包](https://leetcode-cn.com/problems/shopping-offers)   |[16](https://leetcode-cn.com/problems/shopping-offers/solution)|55.9%|中等|14.27%|
|802|[找到最终的安全状态](https://leetcode-cn.com/problems/find-eventual-safe-states)   |[12](https://leetcode-cn.com/problems/find-eventual-safe-states/solution)|44.9%|中等|14.19%|
|98|[验证二叉搜索树](https://leetcode-cn.com/problems/validate-binary-search-tree)   |[131](https://leetcode-cn.com/problems/validate-binary-search-tree/solution)|28.1%|中等|14.09%|
|947|[移除最多的同行或同列石头](https://leetcode-cn.com/problems/most-stones-removed-with-same-row-or-column)   |[7](https://leetcode-cn.com/problems/most-stones-removed-with-same-row-or-column/solution)|45.5%|中等|13.96%|
|417|[太平洋大西洋水流问题](https://leetcode-cn.com/problems/pacific-atlantic-water-flow)   |[17](https://leetcode-cn.com/problems/pacific-atlantic-water-flow/solution)|39.3%|中等|13.81%|
|897|[递增顺序查找树](https://leetcode-cn.com/problems/increasing-order-search-tree)   |[25](https://leetcode-cn.com/problems/increasing-order-search-tree/solution)|64.0%|简单|13.69%|
|576|[出界的路径数](https://leetcode-cn.com/problems/out-of-boundary-paths)   |[13](https://leetcode-cn.com/problems/out-of-boundary-paths/solution)|34.4%|中等|13.59%|
|113|[路径总和 II](https://leetcode-cn.com/problems/path-sum-ii)   |[84](https://leetcode-cn.com/problems/path-sum-ii/solution)|57.9%|中等|13.41%|
|785|[判断二分图](https://leetcode-cn.com/problems/is-graph-bipartite)   |[27](https://leetcode-cn.com/problems/is-graph-bipartite/solution)|41.9%|中等|13.34%|
|690|[员工的重要性](https://leetcode-cn.com/problems/employee-importance)   |[25](https://leetcode-cn.com/problems/employee-importance/solution)|55.4%|简单|12.84%|
|685|[冗余连接 II](https://leetcode-cn.com/problems/redundant-connection-ii)   |[12](https://leetcode-cn.com/problems/redundant-connection-ii/solution)|32.5%|困难|12.78%|
|979|[在二叉树中分配硬币](https://leetcode-cn.com/problems/distribute-coins-in-binary-tree)   |[10](https://leetcode-cn.com/problems/distribute-coins-in-binary-tree/solution)|64.3%|中等|12.53%|
|257|[二叉树的所有路径](https://leetcode-cn.com/problems/binary-tree-paths)   |[81](https://leetcode-cn.com/problems/binary-tree-paths/solution)|61.2%|简单|12.39%|
|513|[找树左下角的值](https://leetcode-cn.com/problems/find-bottom-left-tree-value)   |[48](https://leetcode-cn.com/problems/find-bottom-left-tree-value/solution)|67.4%|中等|11.41%|
|210|[课程表 II](https://leetcode-cn.com/problems/course-schedule-ii)   |[38](https://leetcode-cn.com/problems/course-schedule-ii/solution)|45.5%|中等|11.26%|
|116|[填充每个节点的下一个右侧节点指针](https://leetcode-cn.com/problems/populating-next-right-pointers-in-each-node)   |[58](https://leetcode-cn.com/problems/populating-next-right-pointers-in-each-node/solution)|51.2%|中等|11.2%|
|490|[迷宫](https://leetcode-cn.com/problems/the-maze)   |[13](https://leetcode-cn.com/problems/the-maze/solution)|43.7%|中等|11.04%|
|430|[扁平化多级双向链表](https://leetcode-cn.com/problems/flatten-a-multilevel-doubly-linked-list)   |[30](https://leetcode-cn.com/problems/flatten-a-multilevel-doubly-linked-list/solution)|44.0%|中等|10.74%|
|323|[无向图中连通分量的数目](https://leetcode-cn.com/problems/number-of-connected-components-in-an-undirected-graph)   |[21](https://leetcode-cn.com/problems/number-of-connected-components-in-an-undirected-graph/solution)|52.7%|中等|10.25%|
|129|[求根到叶子节点数字之和](https://leetcode-cn.com/problems/sum-root-to-leaf-numbers)   |[60](https://leetcode-cn.com/problems/sum-root-to-leaf-numbers/solution)|60.3%|中等|9.64%|
|100|[相同的树](https://leetcode-cn.com/problems/same-tree)   |[148](https://leetcode-cn.com/problems/same-tree/solution)|55.8%|简单|9.06%|
|733|[图像渲染](https://leetcode-cn.com/problems/flood-fill)   |[38](https://leetcode-cn.com/problems/flood-fill/solution)|52.4%|简单|8.72%|
|841|[钥匙和房间](https://leetcode-cn.com/problems/keys-and-rooms)   |[29](https://leetcode-cn.com/problems/keys-and-rooms/solution)|58.5%|中等|8.47%|
|529|[扫雷游戏](https://leetcode-cn.com/problems/minesweeper)   |[21](https://leetcode-cn.com/problems/minesweeper/solution)|57.9%|中等|6.77%|
|1254|[统计封闭岛屿的数目](https://leetcode-cn.com/problems/number-of-closed-islands)   |[29](https://leetcode-cn.com/problems/number-of-closed-islands/solution)|57.3%|中等|6.45%|
|872|[叶子相似的树](https://leetcode-cn.com/problems/leaf-similar-trees)   |[36](https://leetcode-cn.com/problems/leaf-similar-trees/solution)|61.4%|简单|4.97%|
|117|[填充每个节点的下一个右侧节点指针 II](https://leetcode-cn.com/problems/populating-next-right-pointers-in-each-node-ii)   |[47](https://leetcode-cn.com/problems/populating-next-right-pointers-in-each-node-ii/solution)|43.1%|中等|3.23%|
|1242|[多线程网页爬虫](https://leetcode-cn.com/problems/web-crawler-multithreaded)   |[3](https://leetcode-cn.com/problems/web-crawler-multithreaded/solution)|35.9%|中等|&nbsp;|
|1145|[二叉树着色游戏](https://leetcode-cn.com/problems/binary-tree-coloring-game)   |[17](https://leetcode-cn.com/problems/binary-tree-coloring-game/solution)|37.2%|中等|&nbsp;|
|1110|[删点成林](https://leetcode-cn.com/problems/delete-nodes-and-return-forest)   |[24](https://leetcode-cn.com/problems/delete-nodes-and-return-forest/solution)|55.0%|中等|&nbsp;|
|1273|[删除树节点](https://leetcode-cn.com/problems/delete-tree-nodes)   |[16](https://leetcode-cn.com/problems/delete-tree-nodes/solution)|48.9%|中等|&nbsp;|
|1080|[根到叶路径上的不足节点](https://leetcode-cn.com/problems/insufficient-nodes-in-root-to-leaf-paths)   |[17](https://leetcode-cn.com/problems/insufficient-nodes-in-root-to-leaf-paths/solution)|41.8%|中等|&nbsp;|
|1034|[边框着色](https://leetcode-cn.com/problems/coloring-a-border)   |[13](https://leetcode-cn.com/problems/coloring-a-border/solution)|39.0%|中等|&nbsp;|
|1136|[平行课程](https://leetcode-cn.com/problems/parallel-courses)   |[5](https://leetcode-cn.com/problems/parallel-courses/solution)|49.1%|困难|&nbsp;|
|1102|[得分最高的路径](https://leetcode-cn.com/problems/path-with-maximum-minimum-value)   |[11](https://leetcode-cn.com/problems/path-with-maximum-minimum-value/solution)|25.8%|中等|&nbsp;|
|1028|[从先序遍历还原二叉树](https://leetcode-cn.com/problems/recover-a-tree-from-preorder-traversal)   |[16](https://leetcode-cn.com/problems/recover-a-tree-from-preorder-traversal/solution)|58.7%|困难|&nbsp;|
|1020|[飞地的数量](https://leetcode-cn.com/problems/number-of-enclaves)   |[9](https://leetcode-cn.com/problems/number-of-enclaves/solution)|47.9%|中等|&nbsp;|
|1061|[按字典序排列最小的等效字符串](https://leetcode-cn.com/problems/lexicographically-smallest-equivalent-string)   |[7](https://leetcode-cn.com/problems/lexicographically-smallest-equivalent-string/solution)|46.6%|中等|&nbsp;|
|971|[翻转二叉树以匹配先序遍历](https://leetcode-cn.com/problems/flip-binary-tree-to-match-preorder-traversal)   |[10](https://leetcode-cn.com/problems/flip-binary-tree-to-match-preorder-traversal/solution)|41.4%|中等|&nbsp;|
|959|[由斜杠划分区域](https://leetcode-cn.com/problems/regions-cut-by-slashes)   |[11](https://leetcode-cn.com/problems/regions-cut-by-slashes/solution)|63.1%|中等|&nbsp;|
|886|[可能的二分法](https://leetcode-cn.com/problems/possible-bipartition)   |[7](https://leetcode-cn.com/problems/possible-bipartition/solution)|34.0%|中等|&nbsp;|
|851|[喧闹和富有](https://leetcode-cn.com/problems/loud-and-rich)   |[10](https://leetcode-cn.com/problems/loud-and-rich/solution)|41.9%|中等|&nbsp;|
|489|[扫地机器人](https://leetcode-cn.com/problems/robot-room-cleaner)   |[5](https://leetcode-cn.com/problems/robot-room-cleaner/solution)|73.7%|困难|&nbsp;|
|827|[最大人工岛](https://leetcode-cn.com/problems/making-a-large-island)   |[16](https://leetcode-cn.com/problems/making-a-large-island/solution)|38.0%|困难|&nbsp;|
|756|[金字塔转换矩阵](https://leetcode-cn.com/problems/pyramid-transition-matrix)   |[10](https://leetcode-cn.com/problems/pyramid-transition-matrix/solution)|52.3%|中等|&nbsp;|
|749|[隔离病毒](https://leetcode-cn.com/problems/contain-virus)   |[5](https://leetcode-cn.com/problems/contain-virus/solution)|48.0%|困难|&nbsp;|
|737|[句子相似性 II](https://leetcode-cn.com/problems/sentence-similarity-ii)   |[6](https://leetcode-cn.com/problems/sentence-similarity-ii/solution)|36.0%|中等|&nbsp;|
|533|[孤独像素 II](https://leetcode-cn.com/problems/lonely-pixel-ii)   |[5](https://leetcode-cn.com/problems/lonely-pixel-ii/solution)|45.0%|中等|&nbsp;|
|531|[孤独像素 I](https://leetcode-cn.com/problems/lonely-pixel-i)   |[14](https://leetcode-cn.com/problems/lonely-pixel-i/solution)|65.1%|中等|&nbsp;|
|1059|[从始点到终点的所有路径](https://leetcode-cn.com/problems/all-paths-from-source-lead-to-destination)   |[5](https://leetcode-cn.com/problems/all-paths-from-source-lead-to-destination/solution)|26.5%|中等|&nbsp;|
|473|[火柴拼正方形](https://leetcode-cn.com/problems/matchsticks-to-square)   |[14](https://leetcode-cn.com/problems/matchsticks-to-square/solution)|35.8%|中等|&nbsp;|
|472|[连接词](https://leetcode-cn.com/problems/concatenated-words)   |[10](https://leetcode-cn.com/problems/concatenated-words/solution)|43.9%|困难|&nbsp;|
|366|[寻找完全二叉树的叶子节点](https://leetcode-cn.com/problems/find-leaves-of-binary-tree)   |[15](https://leetcode-cn.com/problems/find-leaves-of-binary-tree/solution)|69.3%|中等|&nbsp;|
|339|[嵌套列表权重和](https://leetcode-cn.com/problems/nested-list-weight-sum)   |[9](https://leetcode-cn.com/problems/nested-list-weight-sum/solution)|78.1%|简单|&nbsp;|
|261|[以图判树](https://leetcode-cn.com/problems/graph-valid-tree)   |[19](https://leetcode-cn.com/problems/graph-valid-tree/solution)|42.7%|中等|&nbsp;|
