intractability(难解性)

还未搞懂这部分 P与NP问题 待续

O的定义

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大O()的定义:

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没有超过4次所以可以 = O(n4)

小o()定义

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时间复杂性:重点:运行步数,
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Boolean sums 布尔运算
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Resources used by all reasonable machines are withn a polynomial factor of one another

P and NP

NP: Is the class of all search problems
P : Is the class of all tractable (易处理) search problems
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Q: Which problems are in P?
A: The ones that we are solving with efficient algorithms.

Q: Which problems are intractable (in NP but not in P) ?
A: Diffclut to know (no one has found even one such problem).

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Tip(专业名词英语对照): https://wenku.baidu.com/view/74fd4667647d27284b7351c0.html

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