| 802 | Find Eventual Safe States | Medium |
| 814 | Binary Tree Pruning | Medium |
| 827 | Making A Large Island | Hard |
| 834 | Sum of Distances in Tree | Hard |
| 839 | Similar String Groups | Hard |
| 841 | Keys and Rooms | Medium |
| 851 | Loud and Rich | Medium |
| 863 | All Nodes Distance K in Binary Tree | Medium |
| 865 | Smallest Subtree with all the Deepest Nodes | Medium |
| 872 | Leaf-Similar Trees | Easy |
| 886 | Possible Bipartition | Medium |
| 897 | Increasing Order Search Tree | Easy |
| 924 | Minimize Malware Spread | Hard |
| 928 | Minimize Malware Spread II | Hard |
| 934 | Shortest Bridge | Medium |
| 938 | Range Sum of BST | Easy |
| 947 | Most Stones Removed with Same Row or Column | Medium |
| 951 | Flip Equivalent Binary Trees | Medium |
| 959 | Regions Cut By Slashes | Medium |
| 965 | Univalued Binary Tree | Easy |
| 968 | Binary Tree Cameras | Hard |
| 971 | Flip Binary Tree To Match Preorder Traversal | Medium |
| 979 | Distribute Coins in Binary Tree | Medium |
| 987 | Vertical Order Traversal of a Binary Tree | Hard |
| 988 | Smallest String Starting From Leaf | Medium |
| 993 | Cousins in Binary Tree | Easy |
| 1020 | Number of Enclaves | Medium |
| 1022 | Sum of Root To Leaf Binary Numbers | Easy |
| 1026 | Maximum Difference Between Node and Ancestor | Medium |
| 1028 | Recover a Tree From Preorder Traversal | Hard |