一样情况

#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;
int tot;
long long ans=1,ans1;
string s;
struct nond{
    int first,second,pos;
}v[101];
int gcd(long long x,long long y){
    return x==0?y:gcd(y%x,x);
}
int main(){
    cin>>s;
    if(s[0]!='-')    s='+'+s;
    int len=s.length(),sum=0;
    for(int i=0;i<len;i++){
        if(s[i]>='0'&&s[i]<='9')    sum*=10,sum+=s[i]-'0';
        else{
            if(s[i]=='/')    v[tot].first=sum;
            else{
                v[tot].second=sum;
                if(s[i]=='+')    v[++tot].pos=1;
                else if(s[i]=='-')    v[++tot].pos=-1; 
            }sum=0;
        }
    }
    v[tot].second=sum;
    ans=v[1].second;
    for(int i=2;i<=tot;i++)
        ans=(v[i].second*ans)/gcd(v[i].second,ans);
    for(int i=1;i<=tot;i++){
        int GCD=gcd(v[i].first,v[i].second);
        v[i].first/=GCD;v[i].second/=GCD;
        v[i].first*=ans/v[i].second;
        ans1+=v[i].pos*v[i].first; 
    }
    if(ans/gcd(ans,abs(ans1))==1)    cout<<ans1/gcd(abs(ans1),ans);
    else cout<<ans1/gcd(abs(ans1),ans)<<"/"<<ans/gcd(abs(ans1),ans);
}