Tags：搜索
作业部落
评论地址
PPT中会讲的很详细
当搜索的各项互不影响（如共\(n\)个物品前\(n/2\)个物品选不选和后\(n/2\)个物品选不选互不干扰）且状态数小得可怜的时候可以考虑双向搜索（MITM）
实现非常灵活，具体看题
精髓是：用空间换时间
- [[SPOJ4580]ABCDEF](https://www.luogu.org/problemnew/show/SP4580)☃☃
- [[NOI2001]方程的解数](http://cogs.pro:8080/cogs/problem/problem.php?pid=304)☃☃
- [[TopCoder14580] EllysRPS](https://vjudge.net/problem/TopCoder-14580)☃☃☃
- [[BZOJ4800]Ice Hockey World Championship](http://push.mogician.cn/lydsy/JudgeOnline/4800.html)☃☃☃
- [[Codeforces888E]Maximum Subsequence](https://www.luogu.org/problemnew/show/CF888E)☃☃☃
- [[ZOJ3777] Problem Arrangement](https://vjudge.net/problem/ZOJ-3777)☃☃
- [八数码难题](https://www.luogu.org/problemnew/show/P1379)☃☃☃