coderforce Finite or not?

C. Finite or not?
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output

You are given several queries. Each query consists of three integers ppqq and bb. You need to answer whether the result of p/qp/q in notation with base bb is a finite fraction.

A fraction in notation with base bb is finite if it contains finite number of numerals after the decimal point. It is also possible that a fraction has zero numerals after the decimal point.

Input

The first line contains a single integer nn (1n1051≤n≤105) — the number of queries.

Next nn lines contain queries, one per line. Each line contains three integers ppqq, and bb (0p10180≤p≤10181q10181≤q≤10182b10182≤b≤1018). All numbers are given in notation with base 1010.

Output

For each question, in a separate line, print Finite if the fraction is finite and Infinite otherwise.

Examples
input
Copy
2
6 12 10
4 3 10
output
Copy
Finite
Infinite
input
Copy
4
1 1 2
9 36 2
4 12 3
3 5 4
output
Copy
Finite
Finite
Finite
Infinite
Note

612=12=0,510612=12=0,510

43=1,(3)1043=1,(3)10

936=14=0,012936=14=0,012

412=13=0,13

题意:给你p,q让你判断在b进制下p/q是否为有限小数。

思路:

十进制小数转二进制,

如0.125,小数乘以进制取整数0,小数0.25乘以进制取整数0,小数0.5乘以进制取整数1,且乘到1停止

0.125对应  0.001  即0*(1/2)+0*(1/4)+1*(1/8)=0.125,回看过程,1/q*b*b....每次取整数,最后等于1。

这类似于b对q的约分,所以只要看q的质因子数是否包含在b中。

注意:在此之前要将p/q化为最简分数。

#include<bits/stdc++.h>
#define ll long long
using namespace std;
ll gcd(ll x,ll y){
   ll z;
   while(x){
      z=y%x;
      y=x;
      x=z;
   }
   return y;
}
int main(){
    //freopen("data.in","r",stdin);
    int n;
    scanf("%d",&n);
    while(n--){
       ll p,q,d;
       scanf("%lld%lld%lld",&p,&q,&d);
       if(p==0||q==1){
         printf("Finite\n");
         continue;
       }
       ll g=gcd(p,q);
       p=p/g;
       q=q/g;

       while(q!=1&&d!=1){
            d=gcd(q,d);
          q=q/d;
       }
       if(q==1){
        printf("Finite\n");
       }else
        printf("Infinite\n");

    }
    return 0;
}

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转载自blog.csdn.net/wxl7777/article/details/80341552