Power of Cryptography
Description Current work in cryptography involves (among other things) large prime numbers and computing powers of numbers among these primes. Work in this area has resulted in the practical use of results from number theory and other branches of mathematics once considered to be only of theoretical interest.
This problem involves the efficient computation of integer roots of numbers. Given an integer n>=1 and an integer p>= 1 you have to write a program that determines the n th positive root of p. In this problem, given such integers n and p, p will always be of the form k to the nth. power, for an integer k (this integer is what your program must find). Input The input consists of a sequence of integer pairs n and p with each integer on a line by itself. For all such pairs 1<=n<= 200, 1<=p<10101 and there exists an integer k, 1<=k<=109 such that kn = p.
Output For each integer pair n and p the value k should be printed, i.e., the number k such that k n =p.
Sample Input 2 16 3 27 7 4357186184021382204544 Sample Output 4 3 1234 Source |
看了discuss, double水过, 但好像需要用C++. G++WA,不知道为啥?现在就不求甚解吧。。。
#include <cstdio> #include <cmath> using namespace std; int main() { double p,n; while(scanf("%lf %lf",&n, &p)!=EOF) { printf("%.0lf\n",pow(p,1/n)); } return 0; }