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The Euler function Problem Description The Euler function phi is an important kind of function in number theory, (n) represents the amount of the numb 阅读全文
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GCD Again Problem Description Do you have spent some time to think and try to solve those unsolved problem after one ACM contest? No? Oh, you must do 阅读全文
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欧拉函数证明 欧拉函数定义：定义一个数n，φ(n)为不大于n的，与n互质的数的个数。 证明方法用到容斥定理：容斥定理的原理如图： A∪B∪C=A+B+C - A∩B - B∩C - A∩C + A∩B∩C; 欧拉函数证明： 小于等于n的基数有n个，讨论所有n的素因子，只要是素因子的倍数的是都不是n的 阅读全文
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Assignments Problem Description In a factory, there are N workers to finish two types of tasks (A and B). Each type has N tasks. Each task of type A n 阅读全文