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Re:简单解释

Posted by xhpku at 2018-02-01 09:53:35 on Problem 2411
In Reply To:简单解释 Posted by:Sayakiss at 2010-08-09 19:24:25
> 用2进制的01表示不放还是放
> 第i行只和i-1行有关
> 枚举i-1行的每个状态,推出由此状态能达到的i行状态
> 如果i-1行的出发状态某处未放,必然要在i行放一个竖的方块,所以我对上一行状态按位取反之后的状态就是放置了竖方块的状态。
> 然后用搜索扫一道在i行放横着的方块的所有可能,并且把这些状态累加上i-1的出发状态的方法数,如果该方法数为0,直接continue。
> 举个例子
> 2 4
> 1111
> 1111
> 状态可以由
> 1100 0000 0110 0011 1111
> 0000 0000 0000 0000 0000
> 这五种i-1的状态达到,故2 4 的答案为5


你真的好棒啊!

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