| [114. Flatten Binary Tree to Linked List](https://leetcode.com/problems/flatten-binary-tree-to-linked-list/?show=1) | [114. 二叉树展开为链表](https://leetcode.cn/problems/flatten-binary-tree-to-linked-list/?show=1) |
| [116. Populating Next Right Pointers in Each Node](https://leetcode.com/problems/populating-next-right-pointers-in-each-node/?show=1) | [116. 填充每个节点的下一个右侧节点指针](https://leetcode.cn/problems/populating-next-right-pointers-in-each-node/?show=1) |
| [124. Binary Tree Maximum Path Sum](https://leetcode.com/problems/binary-tree-maximum-path-sum/?show=1) | [124. 二叉树中的最大路径和](https://leetcode.cn/problems/binary-tree-maximum-path-sum/?show=1) |
| [1245. Tree Diameter](https://leetcode.com/problems/tree-diameter/?show=1)🔒 | [1245. 树的直径](https://leetcode.cn/problems/tree-diameter/?show=1)🔒 |
| [1261. Find Elements in a Contaminated Binary Tree](https://leetcode.com/problems/find-elements-in-a-contaminated-binary-tree/?show=1) | [1261. 在受污染的二叉树中查找元素](https://leetcode.cn/problems/find-elements-in-a-contaminated-binary-tree/?show=1) |
| [129. Sum Root to Leaf Numbers](https://leetcode.com/problems/sum-root-to-leaf-numbers/?show=1) | [129. 求根节点到叶节点数字之和](https://leetcode.cn/problems/sum-root-to-leaf-numbers/?show=1) |
| [1315. Sum of Nodes with Even-Valued Grandparent](https://leetcode.com/problems/sum-of-nodes-with-even-valued-grandparent/?show=1) | [1315. 祖父节点值为偶数的节点和](https://leetcode.cn/problems/sum-of-nodes-with-even-valued-grandparent/?show=1) |
| [1367. Linked List in Binary Tree](https://leetcode.com/problems/linked-list-in-binary-tree/?show=1) | [1367. 二叉树中的列表](https://leetcode.cn/problems/linked-list-in-binary-tree/?show=1) |
| [1372. Longest ZigZag Path in a Binary Tree](https://leetcode.com/problems/longest-zigzag-path-in-a-binary-tree/?show=1) | [1372. 二叉树中的最长交错路径](https://leetcode.cn/problems/longest-zigzag-path-in-a-binary-tree/?show=1) |
| [1373. Maximum Sum BST in Binary Tree](https://leetcode.com/problems/maximum-sum-bst-in-binary-tree/?show=1) | [1373. 二叉搜索子树的最大键值和](https://leetcode.cn/problems/maximum-sum-bst-in-binary-tree/?show=1) |
| [1376. Time Needed to Inform All Employees](https://leetcode.com/problems/time-needed-to-inform-all-employees/?show=1) | [1376. 通知所有员工所需的时间](https://leetcode.cn/problems/time-needed-to-inform-all-employees/?show=1) |
| [1379. Find a Corresponding Node of a Binary Tree in a Clone of That Tree](https://leetcode.com/problems/find-a-corresponding-node-of-a-binary-tree-in-a-clone-of-that-tree/?show=1) | [1379. 找出克隆二叉树中的相同节点](https://leetcode.cn/problems/find-a-corresponding-node-of-a-binary-tree-in-a-clone-of-that-tree/?show=1) |
| [1430. Check If a String Is a Valid Sequence from Root to Leaves Path in a Binary Tree](https://leetcode.com/problems/check-if-a-string-is-a-valid-sequence-from-root-to-leaves-path-in-a-binary-tree/?show=1)🔒 | [1430. 判断给定的序列是否是二叉树从根到叶的路径](https://leetcode.cn/problems/check-if-a-string-is-a-valid-sequence-from-root-to-leaves-path-in-a-binary-tree/?show=1)🔒 |
| [1443. Minimum Time to Collect All Apples in a Tree](https://leetcode.com/problems/minimum-time-to-collect-all-apples-in-a-tree/?show=1) | [1443. 收集树上所有苹果的最少时间](https://leetcode.cn/problems/minimum-time-to-collect-all-apples-in-a-tree/?show=1) |
| [1448. Count Good Nodes in Binary Tree](https://leetcode.com/problems/count-good-nodes-in-binary-tree/?show=1) | [1448. 统计二叉树中好节点的数目](https://leetcode.cn/problems/count-good-nodes-in-binary-tree/?show=1) |
| [145. Binary Tree Postorder Traversal](https://leetcode.com/problems/binary-tree-postorder-traversal/?show=1) | [145. 二叉树的后序遍历](https://leetcode.cn/problems/binary-tree-postorder-traversal/?show=1) |
| [1457. Pseudo-Palindromic Paths in a Binary Tree](https://leetcode.com/problems/pseudo-palindromic-paths-in-a-binary-tree/?show=1) | [1457. 二叉树中的伪回文路径](https://leetcode.cn/problems/pseudo-palindromic-paths-in-a-binary-tree/?show=1) |
| [1602. Find Nearest Right Node in Binary Tree](https://leetcode.com/problems/find-nearest-right-node-in-binary-tree/?show=1)🔒 | [1602. 找到二叉树中最近的右侧节点](https://leetcode.cn/problems/find-nearest-right-node-in-binary-tree/?show=1)🔒 |
| [1612. Check If Two Expression Trees are Equivalent](https://leetcode.com/problems/check-if-two-expression-trees-are-equivalent/?show=1)🔒 | [1612. 检查两棵二叉表达式树是否等价](https://leetcode.cn/problems/check-if-two-expression-trees-are-equivalent/?show=1)🔒 |
| [1740. Find Distance in a Binary Tree](https://leetcode.com/problems/find-distance-in-a-binary-tree/?show=1)🔒 | [1740. 找到二叉树中的距离](https://leetcode.cn/problems/find-distance-in-a-binary-tree/?show=1)🔒 |
| [2049. Count Nodes With the Highest Score](https://leetcode.com/problems/count-nodes-with-the-highest-score/?show=1) | [2049. 统计最高分的节点数目](https://leetcode.cn/problems/count-nodes-with-the-highest-score/?show=1) |
| [559. Maximum Depth of N-ary Tree](https://leetcode.com/problems/maximum-depth-of-n-ary-tree/?show=1) | [559. N 叉树的最大深度](https://leetcode.cn/problems/maximum-depth-of-n-ary-tree/?show=1) |
| [563. Binary Tree Tilt](https://leetcode.com/problems/binary-tree-tilt/?show=1) | [563. 二叉树的坡度](https://leetcode.cn/problems/binary-tree-tilt/?show=1) |
| [572. Subtree of Another Tree](https://leetcode.com/problems/subtree-of-another-tree/?show=1) | [572. 另一棵树的子树](https://leetcode.cn/problems/subtree-of-another-tree/?show=1) |
| [1443. Minimum Time to Collect All Apples in a Tree](https://leetcode.com/problems/minimum-time-to-collect-all-apples-in-a-tree/?show=1) | [1443. 收集树上所有苹果的最少时间](https://leetcode.cn/problems/minimum-time-to-collect-all-apples-in-a-tree/?show=1) |
| [200. Number of Islands](https://leetcode.com/problems/number-of-islands/?show=1) | [200. 岛屿数量](https://leetcode.cn/problems/number-of-islands/?show=1) |
| [2049. Count Nodes With the Highest Score](https://leetcode.com/problems/count-nodes-with-the-highest-score/?show=1) | [2049. 统计最高分的节点数目](https://leetcode.cn/problems/count-nodes-with-the-highest-score/?show=1) |
| [200. Number of Islands](https://leetcode.com/problems/number-of-islands/?show=1) | [200. 岛屿数量](https://leetcode.cn/problems/number-of-islands/?show=1) |
| [947. Most Stones Removed with Same Row or Column](https://leetcode.com/problems/most-stones-removed-with-same-row-or-column/?show=1) | [947. 移除最多的同行或同列石头](https://leetcode.cn/problems/most-stones-removed-with-same-row-or-column/?show=1) |
这样修改后，只要找到一个答案，for 循环的后续递归穷举都会被阻断。也许你可以在 N 皇后问题的代码框架上，稍加修改，写一个解数独的算法？可以参考我的这篇文章 [回溯算法秒杀数独问题](https://labuladong.github.io/article/fname.html?fname=sudoku)。
再简单拓展一下，有可能题目不需要你计算出 N 皇后问题的所有具体结果，而仅仅问你共有几种解法，应该怎么做呢？
