编程介的小学生 2017-04-02 13:39 采纳率: 20.5%
浏览 739
已采纳

Discrete Logging

Given a prime P, 2 <= P < 2^31, an integer B, 2 <= B < P, and an integer N, 2 <= N < P, compute the discrete logarithm of N, base B, modulo P. That is, find an integer L such that

B^L == N (mod P)

Input

Read several lines of input, each containing P,B,N separated by a space, and for each line print the logarithm on a separate line.

Output

If there are several, print the smallest; if there is none, print "no solution".

The solution to this problem requires a well known result in number theory that is probably expected of you for Putnam but not ACM competitions. It is Fermat's theorem that states

B^(P-1) == 1 (mod P)

for any prime P and some other (fairly rare) numbers known as base-B pseudoprimes. A rarer subset of the base-B pseudoprimes, known as Carmichael numbers, are pseudoprimes for every base between 2 and P-1. A corollary to Fermat's theorem is that for any m

B^(-m) == B^(P-1-m) (mod P) .

Sample Input

5 2 1
5 2 2
5 2 3
5 2 4
5 3 1
5 3 2
5 3 3
5 3 4
5 4 1
5 4 2
5 4 3
5 4 4
12345701 2 1111111
1111111121 65537 1111111111

Sample Output

0
1
3
2
0
3
1
2
0
no solution
no solution
1
9584351
462803587

  • 写回答

1条回答 默认 最新

  • threenewbee 2017-04-16 15:27
    关注
    本回答被题主选为最佳回答 , 对您是否有帮助呢?
    评论

报告相同问题?

悬赏问题

  • ¥15 python的qt5界面
  • ¥15 无线电能传输系统MATLAB仿真问题
  • ¥50 如何用脚本实现输入法的热键设置
  • ¥20 我想使用一些网络协议或者部分协议也行,主要想实现类似于traceroute的一定步长内的路由拓扑功能
  • ¥30 深度学习,前后端连接
  • ¥15 孟德尔随机化结果不一致
  • ¥15 apm2.8飞控罗盘bad health,加速度计校准失败
  • ¥15 求解O-S方程的特征值问题给出边界层布拉休斯平行流的中性曲线
  • ¥15 谁有desed数据集呀
  • ¥20 手写数字识别运行c仿真时,程序报错错误代码sim211-100