「BJOI2019」奥术神杖（AC自动机+DP）
作者：互联网
文章目录
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solution
令
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Magic=V_i\times V_j\times V_k...
Magic=Vi×Vj×Vk...
这里对
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\sqrt[c]{Magic}
cMagic
有一个很巧妙的转换——取对数
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\sqrt[c]{Magic}=(Magic)^{\frac{1}{c}}=e^{log_e(Magic)^{\frac{1}{c}}}
cMagic
=(Magic)c1=eloge(Magic)c1
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log_e\ Magic^{\frac{1}{c}}=\frac{1}{c}log_e\ Magic=\frac{1}{c}log_e(V_i\times V_j\times V_k...)
loge Magicc1=c1loge Magic=c1loge(Vi×Vj×Vk...)
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=\frac{1}{c}\times (log_eV_i+log_eV_j+log_eV_k...)
=c1×(logeVi+logeVj+logeVk...)
于是就成功把神力值的相乘开方变为了相加
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(\frac{log_eV_i+log_eV_j+log_eV_k...}{c})_{max}
(clogeVi+logeVj+logeVk...)max
标签：BJOI2019,奥术,Magic,int,AC,trie,maxn,now,dp 来源： https://blog.csdn.net/Emm_Titan/article/details/111657444