solution1
直观上的分数处理
#include <iostream>
using namespace std;
int main()
{
printf("1048575/524288");
return 0;
}
#include<stdio.h>
#include<math.h>
typedef long long ll;
struct fraction{
ll up, down;
};
ll gcd(ll a, ll b){
if(!b) return a;
return gcd(b, a % b);
}
fraction r(fraction f){
if(gcd(f.down, f.up) > 1){
f.down /= gcd(f.down, f.up);
f.up /= gcd(f.down, f.up);
}
return f;
}
fraction add(fraction f1, fraction f2){
fraction f;
f.down = f1.down * f2.down;
f.up = f1.up * f2.down + f2.up * f1.down;
return r(f);
}
int main(){
fraction f, t;
f.up = f.down = 1;
for(ll i = 2; i <= pow(2, 19); i *= 2){
t.up = 1;
t.down = i;
printf("%lld %lld\n", t.down, f.up);
f = add(f, t);
}
printf("%lld %lld, %lld %lld", f.up / f.down, f.up % f.down, f.up, f.down);
return 0;
}
solution2
手动通分计算为
(219+218+217……+20)/219= (220-1)/219
- 20+21+22+……+2n-1 = 2n-1
- 较大的数若比 较小的数 的两倍大于或者小1,则两者互质
#include<stdio.h>
#include<math.h>
typedef long long ll;
int main(){
printf("%lld/%lld", (ll) pow(2, 20) - 1, (ll) pow(2, 19));//注意别漏了强转double -> ll
return 0;
}