> For the complete documentation index, see [llms.txt](https://dfine.gitbook.io/leetcode/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://dfine.gitbook.io/leetcode/292.nim_game.md). # 282.Nim Game **292.Nim Game** 难度:Easy > 你和你的朋友，两个人一起玩 Nim游戏：桌子上有一堆石头，每次你们轮流拿掉 1 - 3 块石头。拿掉最后一块石头的人就是获胜者。你作为先手。你们是聪明人，每一步都是最优解。编写一个函数，来判断你是否可以在给定石头数量的情况下赢得游戏。示例: ``` 输入: 4 输出: false 解释: 如果堆中有 4 块石头，那么你永远不会赢得比赛；因为无论你拿走 1 块、2 块还是 3 块石头，最后一块石头总是会被你的朋友拿走。 ``` 方法：直接递归是不行的，肯定会超时。解决方法就是保持先手，只要保证最后一个自己拿，那么前面的保证两个人每次拿到的都是(min+max)个数，让对方拿第四块即可。 ``` class Solution { public: bool canWinNim(int n) { if(!n) return false; if(n<4) return true; if(!(n%4)) return false; else return true; } }; ``` --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://dfine.gitbook.io/leetcode/292.nim_game.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.