第十一周 11.8-11.14

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <algorithm>
 4 #include <cmath>
 5 using namespace std;
 6 typedef long long LL;
 7 
 8 LL gcd(LL a,LL b)
 9 {
10     return b?gcd(b,a%b):a;
11 }
12 
13 int main(void)
14 {
15     LL t,w,b;
16     scanf("%I64d%I64d%I64d",&t,&w,&b);
17     LL x,GCD=gcd(w,b),LCM=b/GCD*w;
18     if(log(double(w))+log(double(b))>log(double(t))+log(double(GCD))) x=min(min(w-1,b-1),t);
19     else x=t/LCM*min(w,b)+min(t%LCM,min(w-1,b-1));
20     GCD=gcd(x,t);
21     printf("%I64d/%I64d\n",x/GCD,t/GCD);
22     return 0;
23 }