1034 有理数四则运算 (20分)

#include<stdio.h>
#include<algorithm>
using namespace std;
typedef long long ll;
struct fraction{
    ll up,down;
}temp1,temp2,a1,a2,a3,a4;
int gcd(ll a,ll b){
    if(b==0) return a;
    else return gcd(b,a%b);
}

fraction reduction(fraction result){
    if(result.down<0){
        result.up=-result.up;
        result.down=-result.down;
    }
    if(result.up==0)result.down=1;
    else{
        int d=gcd(abs(result.up),abs(result.down));
        result.up=result.up/d;
        result.down=result.down/d;
    }
    return result;
}
fraction add(fraction f1,fraction f2){
    fraction result;
    result.up=f1.up*f2.down+f1.down*f2.up;
    result.down=f1.down*f2.down;
    return reduction(result);
}
fraction minu(fraction f1,fraction f2){
    fraction result;
    result.up=f1.up*f2.down-f1.down*f2.up;
    result.down=f1.down*f2.down;
    return reduction(result);
}
fraction multi(fraction f1,fraction f2){
    fraction result;
    result.up=f1.up*f2.up;
    result.down=f1.down*f2.down;
    return reduction(result);
}
fraction divide(fraction f1,fraction f2){
    fraction result;
    result.up=f1.up*f2.down;
    result.down=f1.down*f2.up;
    return reduction(result);
}
void showresult(fraction r){
    r=reduction(r);
    if(r.down==0) printf("Inf");
    if(r.down==1) {
        if(r.up<0)printf("(%lld)",r.up);
        else printf("%lld",r.up);
    }
    else if(abs(r.up)>r.down){
        if(r.up<0)printf("(%lld %lld/%lld)",r.up/r.down,abs(r.up)%r.down,r.down);
        else printf("%lld %lld/%lld",r.up/r.down,abs(r.up)%r.down,r.down);
    }else {
        if(r.up<0)printf("(%lld/%lld)",r.up,r.down);
        else printf("%lld/%lld",r.up,r.down);
    }
}

int main(){
    scanf("%lld/%lld %lld/%lld",&temp1.up,&temp1.down,&temp2.up,&temp2.down);
    temp1=reduction(temp1);
    temp2=reduction(temp2);

    a1=add(temp1,temp2);
    a2=minu(temp1,temp2);
    a3=multi(temp1,temp2);
    a4=divide(temp1,temp2);
    showresult(temp1);
    printf(" + ");
    showresult(temp2);
    printf(" = ");
    showresult(a1);
printf("\n");
    showresult(temp1);
    printf(" - ");
    showresult(temp2);
    printf(" = ");
    showresult(a2);
printf("\n");
    showresult(temp1);
    printf(" * ");
    showresult(temp2);
    printf(" = ");
    showresult(a3);
printf("\n");
    showresult(temp1);
    printf(" / ");
    showresult(temp2);
    printf(" = ");
    if(temp2.up==0)
        printf("Inf");
    else showresult(a4);
printf("\n");
}

第一次，参考算法笔记完成，40min