PAT 甲级 1088 Rational Arithmetic

大家注意一下Inf不要写成INF不然就会像个憨批一样扒数据扒半个小时。

#include <bits/stdc++.h>
using namespace std;
struct Fraction {
    long long up, down;
};
long long gcd(long long a, long long b)
{
    if (b == 0) return a;
    while (a != 0) {
        if (b > a) swap(a, b);
        a %= b;
    }
    return b;
}
Fraction Reduction(Fraction f)
{
    // 分母为0的情况没有处理，调用时注意
    // 规整符号
    if (f.down < 0) {
        f.up   = -f.up;
        f.down = -f.down;
    }
    // 分子为0
    if (f.up == 0)
        f.down = 1;
    else {
        int d = gcd(abs(f.up), abs(f.down));
        f.up /= d;
        f.down /= d;
    }
    return f;
}
Fraction Add(Fraction a, Fraction b)
{
    Fraction ans;
    ans.down = a.down * b.down;
    ans.up   = a.up * b.down + a.down * b.up;
    return Reduction(ans);
}
Fraction Minu(Fraction a, Fraction b)
{
    Fraction ans;
    ans.down = a.down * b.down;
    ans.up   = a.up * b.down - a.down * b.up;
    return Reduction(ans);
}
Fraction Multi(Fraction a, Fraction b)
{
    Fraction ans;
    ans.down = a.down * b.down;
    ans.up   = a.up * b.up;
    return Reduction(ans);
}
Fraction Divide(Fraction a, Fraction b)
{
    Fraction ans;
    ans.down = a.down * b.up;
    ans.up   = a.up * b.down;
    return Reduction(ans);
}
void Print(Fraction f)
{
    f = Reduction(f);
    if (f.up < 0) printf("(");
    // 整数
    if (f.down == 1)
        printf("%lld", f.up);
    // 假分数
    else if (abs(f.up) > abs(f.down))
        printf("%lld %lld/%lld", f.up / f.down, abs(f.up) % f.down, f.down);
    // 真分数
    else
        printf("%lld/%lld", f.up, f.down);
    if (f.up < 0) printf(")");
}
int main()
{
    Fraction a, b;
    scanf("%lld/%lld %lld/%lld", &a.up, &a.down, &b.up, &b.down);
    // 加
    Print(a);
    cout << " + ";
    Print(b);
    cout << " = ";
    Print(Add(a, b));
    cout << endl;
    // 减
    Print(a);
    cout << " - ";
    Print(b);
    cout << " = ";
    Print(Minu(a, b));
    cout << endl;
    // 乘
    Print(a);
    cout << " * ";
    Print(b);
    cout << " = ";
    Print(Multi(a, b));
    cout << endl;
    // 除
    Print(a);
    cout << " / ";
    Print(b);
    cout << " = ";
    if (b.up != 0)
        Print(Divide(a, b));
    else
        printf("Inf");
    cout << endl;
}