PAT A1081 Rational Sum 测试点3

#include<stdio.h>
#include<algorithm>
#include<string.h>
#include<iostream>
#include<math.h>
using namespace std;



struct Fraction{
    long long up,down;
}sum,temp;

long long gcd(long long  a,long long b)
{
    return b ==0 ? a : gcd(b,a%b);
}


Fraction Add(Fraction a,Fraction b)
{
    Fraction result;
    result.up=a.up*b.down + b.up*a.down;
    result.down= a.down*b.down;
    return result;
}



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 /=d;
        result.down /=d;
    }
    return result;
}

void showResult(Fraction a)
{
    a=reduction(a);
    if(a.down == 1) printf("%lld",a.up);
    else if( abs(a.up>a.down) )
        printf("%lld %lld/%lld",a.up/a.down,abs(a.up)%a.down,a.down);
    else
        printf("%lld/%lld",a.up,a.down);    
}



int main()
{
    int n;
    cin >> n;
    sum.up=0,sum.down=1;
    for(int i=0;i<n;i++)
    {
        scanf("%lld/%lld",&temp.up,&temp.down);
        sum = Add(sum,temp);
        sum=reduction(sum);  //关键！！！
    } 
    showResult(sum);
    return 0;
}     
    

    
    

从算法笔记上学来的无法通过测试点3，如果在每次相加后的结果化简就能避免sum里面的数据膨胀