题解 + Python/Java/C++/Go 代码：
- Q1 https://leetcode.cn/problems/find-the-original-typed-string-i/solution/xiang-lin-xiang-tong-zi-mu-de-ge-shu-jia-6pxv/
- Q2 https://leetcode.cn/problems/find-subtree-sizes-after-changes/solution/liang-ci-dfszi-ding-xiang-xia-zi-di-xian-k4zj/
- Q3 https://leetcode.cn/problems/maximum-points-tourist-can-earn/solution/jiao-ni-yi-bu-bu-si-kao-dpcong-ji-yi-hua-vro4/
- Q4 https://leetcode.cn/problems/find-the-original-typed-string-ii/solution/zheng-nan-ze-fan-qian-zhui-he-you-hua-dp-5mi9/
具体请看 视频讲解，欢迎点赞关注~