SPOJ Ada and Spring Cleaning(hash)

其他 2021-11-22 01:15

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思路：先计算出前k个字符组成的子串的哈希值，再根据哈希值及递推关系

$x_i = t_i * R^{k-1} + t_{i+1} * R^{k-1} + \cdots + t_{i + k - 1} * R^0$

$x_{i+1} = \left( x_i - t^i * R^{k-1}\right ) * R + t_{i + k}$

具体代码参考：

https://github.com/wuli2496/OJ/blob/master/spoj/Ada%20and%20Spring%20Cleaning/Ada%20and%20Spring%20Cleaning(hash).java