POJ 2407 Relatives

  • 2018-08-07
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题目:

Given n, a positive integer, how many positive integers less than n are relatively prime to n? Two integers a and b are relatively prime if there are no integers x > 1, y > 0, z > 0 such that a = xy and b = xz.

Input:

There are several test cases. For each test case, standard input contains a line with n <= 1,000,000,000. A line containing 0 follows the last case.

Output:

For each test case there should be single line of output answering the question posed above.

Sample Input:

7
12
0

Sample Output:

6
4

题目链接

直接求欧拉函数值。

AC代码:

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