A New Stone Game Time Limit: 1000MS Memory Limit: 30000K Total Submissions: 5113 Accepted: 2806 Description Alice and Bob decide to play a new stone game.At the beginning of the game they pick n(1<=n<=10) piles of stones in a line. Alice and Bob mov…

这真是一道博弈论的好题啊 还是采用OI届的惯用套路,从简单想起 如果只有一堆石子,那么一定先手必胜 如果有两堆石子,那么我们考虑如下两种情况 2.1 两堆石子数量相同,那么无论先手怎么拿,后手都有一种与之对应的方法使两堆重新变得数量相同,直至最后石子被拿完,先手必败 2.2 两堆石子数量不同,那么先手一定有一种策略,可以使两堆石子数量相同,此时状态回归到2.1,后手变成了当前状态的先手,先手必胜 如果有三堆石子呢? 我们一定有一种策略,将三堆石子变为两堆相同的石子,这个稍微理解一下或者手玩一下就…

There is an old stone game.At the beginning of the game the player picks n(1<=n<=50000) piles of stones in a line. The goal is to merge the stones in one pile observing the following rules: At each step of the game,the player can merge two adjoining…

题意:有n个石子堆,每一个都可以轮流做如下操作:选一个石堆,移除至少1个石子,然后可以把这堆石子随便拿几次,随便放到任意的其他石子数不为0的石子堆,也可以不拿.不能操作败. 思路:我们先来证明,如果某个石子数有偶数堆,则先手必败,因为无论先手怎么做,后手都能模仿先手,最后把石子取光.显然全是偶数堆是必败态.如果有奇数堆怎么办?我们就把最大的奇数堆取光,然后把其他奇数堆变成偶数堆.但是一定能保证可以吗?答案是可以.假设奇数堆的石子数为 x1,x2,x3...xn,那么我们分别给每一堆加上x2-x1…

POJ 3252:Round Numbers Time Limit: 2000MS Memory Limit: 65536K Total Submissions: 10099 Accepted: 3669 Description The cows, as you know, have no fingers or thumbs and thus are unable to play Scissors, Paper, Stone' (also known as 'Rock, Paper, Sciss…

http://poj.org/problem?id=3321 http://acm.hdu.edu.cn/showproblem.php?pid=3887 POJ 3321: 题意:给出一棵根节点为1的边不一定的树,然后给出问题:询问区间和 或者 节点值更新. HDU 3887: 题意:和POJ 3321的题意差不多,只不过对每个节点询问不包含该节点的区间和 思路:今天才学了下才知道有DFS序这种东西,加上树状数组处理一下区间和 和 节点更新. DFS序大概就是我们在DFS遍历一棵树的时候,在进…

A New Stone Game Time Limit: 1000MS   Memory Limit: 30000K Total Submissions: 5694   Accepted: 3119 Description Alice and Bob decide to play a new stone game.At the beginning of the game they pick n(1<=n<=10) piles of stones in a line. Alice and Bob…

A New Stone Game Time Limit: 1000MS   Memory Limit: 30000K Total Submissions: 5453   Accepted: 2989 Description Alice and Bob decide to play a new stone game.At the beginning of the game they pick n(1<=n<=10) piles of stones in a line. Alice and Bob…

A New Stone Game Time Limit: 1000MS   Memory Limit: 30000K Total Submissions: 5338   Accepted: 2926 Description Alice and Bob decide to play a new stone game.At the beginning of the game they pick n(1<=n<=10) piles of stones in a line. Alice and Bob…

http://poj.org/problem?id=1740 这个博弈一眼看上去很厉害很高大上让人情不自禁觉得自己不会写,结果又是找规律…… 博弈一般后手胜都比较麻烦,但是主要就是找和先手的对应关系,依然看了题解…… 如果所有石头堆两两配对的话后手对先手的每一步都可以对应走一步,那么此时后手必胜. 如果不是两两配对,先手可以通过一次操作使石头堆两两配对,此时的两两配对局面面对的是后手,所以先手必胜. 不是两两配对时的操作:首先将所有非配对推按大小排序(只有一堆直接取没就可以了): 然后显然不配对…