2021米哈游校园招聘-提前批-编程题1-最简分式

#include <iostream>
#include <string>
using namespace std;
//求最大公约数
int subMax(int x, int y)
{
  int z = 0;
  if (x < y)
  {
    int t = x;
    x = y;
    y = t;
  }
  //辗转相除法
  while (y != 0)
  {
    z = x % y;
    x = y;
    y = z;
  }
  return x;
}
int main()
{
  string str;
  while (getline(cin, str))
  {
    //四种运算符讨论
    int fenzi, fenzi2, fenmu, fenmu2, yueshu, yueshu2;
    switch (str[4])
    {
    case '+':
      //分母相同，不通分
      if (str[2] == str[8])
      {
        int a = (str[0] - '0') + (str[6] - '0');
        int b = str[2] - '0';
        int c = subMax(a, b);
        cout << a / c << "/" << b / c << endl;
      }
      else
      {
        //分母不同，通分
        int btemp = str[2] - '0';
        int dtemp = str[8] - '0';
        int k1 = subMax(btemp, dtemp);//最大公约数
        int k2 = btemp * dtemp / k1;//最小公倍数
        int atemp = str[0] - '0';
        int ctemp = str[6] - '0';
        int fenz = k2 / dtemp * atemp + k2 / btemp * ctemp;
        int yues = subMax(fenz, k2);
        cout << fenz / yues << "/" << k2 << endl;
      }
      break;
    case '-':
      //分母相同，不通分
      if (str[2] == str[8])
      {
        int a, c; 
        int b = str[2] - '0';
        if ((str[0] - '0') < (str[6] - '0'))
        {
          a = (str[6] - '0') - (str[0] - '0');
          c = subMax(a, b);
          cout << "-" << a / c << "/" << b / c << endl;
        }
        else
        {
          a = (str[0] - '0') - (str[6] - '0');
          c = subMax(a, b);
          cout << a / c << "/" << b / c << endl;
        }
      }
      else
      {
        //分母不同，通分
        int flag = 0;
        int btemp = str[2] - '0';
        int dtemp = str[8] - '0';
        int k1 = subMax(btemp, dtemp);//最大公约数
        int k2 = btemp * dtemp / k1;//最小公倍数
        int atemp = str[0] - '0';
        int ctemp = str[6] - '0';
        int fenz = k2 / btemp * atemp - k2 / dtemp * ctemp;
        if (fenz < 0)
        {
          fenz = -fenz;
          flag = 1;
        }
        int yues = subMax(fenz, k2);
        if (flag == 1)
        {
          cout << "-" << fenz / yues << "/" << k2 << endl;
        }
        else
        {
          cout << fenz / yues << "/" << k2 << endl;
        }
      }
      break;
    case '*':
      fenzi = (str[0] - '0') * (str[6] - '0');
      fenmu = (str[2] - '0') * (str[8] - '0');
      yueshu = subMax(fenzi, fenmu);
      cout << fenzi / yueshu << "/" << fenmu / yueshu << endl;
      break;
    case '/':
      fenzi2 = (str[0] - '0') * (str[8] - '0');
      fenmu2 = (str[2] - '0') * (str[6] - '0');
      yueshu2 = subMax(fenzi2, fenmu2);
      cout << fenzi2 / yueshu2 << "/" << fenmu2 / yueshu2 << endl;
      break;
    }
  }
  return 0;
}