1081 Rational Sum

#include <cstdio>
#include <algorithm>
using namespace std;
typedef long long ll;
struct frac{
    ll up;
    ll down;
};
ll gcd(ll a, ll b){
    if(b == 0){
        return a;
    }
    return gcd(b, a % b);
}

frac reduc(frac a){
    if(a.down < 0){
        a.down = -a.down;
        a.up = -a.up;
    }
    if(a.up == 0){
        a.down = 1;
    }else{
        ll d = gcd(abs(a.up), abs(a.down));
        a.up = a.up / d;
        a.down = a.down / d;
    }
    return a;
}

frac add(frac a, frac b){
    frac res;
    res.down = a.down * b.down;
    res.up = a.up*b.down + b.up*a.down;
    return reduc(res);
}
int main() {
    int n;
    scanf("%d", &n);
    frac res,cur;
    res.up=0;
    res.down=1;
    for(int i = 0;i < n; i++){
        scanf("%lld/%lld", &cur.up, &cur.down);
        res = add(res, cur);
    }
    if(res.down == 1){
        printf("%lld\n",res.up);
    }else{
        if(res.up > res.down){
            printf("%lld %lld/%lld\n",res.up / res.down, res.up % res.down, res.down);
        }else{
            printf("%lld/%lld\n", res.up, res.down);
        }
    }
    return 0;
}