olymp2007_ariph

ariph.c

#include <stdio.h>
#include <malloc.h>

void sum(int, int, int, int, long long*);
void multiplication(int, int, int, int, long long*);
int lcm(int, int); // lowest common multiple

int main() {
  int p1, q1, p2, q2;
  long long* ans = (long long*)malloc(2*sizeof(long long)); // answer
  char sign;
  int i = 0;
  int commondivisor;
  
  
  freopen("input.txt", "r", stdin);

  scanf("%d/%d%c%d/%d", &p1, &q1, &sign, &p2, &q2);
  switch (sign) {
    case '+':
      sum(p1, q1, p2, q2, ans);
      break;
    case '-':
      sum(p1, q1, -p2, q2, ans);
      break;
    case '*':
      multiplication(p1, q1, p2, q2, ans);
      break;
    case ':':
      multiplication(p1, q1, q2, p2, ans);
      break;
  }

  //printf("%lld/%lld\n", ans[0], ans[1]);

  commondivisor = abs(ans[0]*ans[1]) / lcm(ans[0], ans[1]);
  printf("%d\n", commondivisor);

  //if (ans[1] < 0) {ans[0] = -ans[0]; ans[1] = -ans[1];}

  ans[0] /= commondivisor;
  ans[1] /= commondivisor;

  printf("%lld/%lld\n", ans[0], ans[1]);

  freopen("output.txt", "w", stdout);

  printf("%lld/%lld\n", ans[0], ans[1]);
}

int lcm(int x, int y) {
  int i = ((x >= y) ? x : y);

  for (i; i < abs(x*y); i++)
    if ((i % x == 0) && (i % y == 0)) {
      printf("lcm - %d\n", i);
      return i;
    }
  printf("lcm - %d\n", x*y);
  return x*y;
}

void sum(int p1, int q1, int p2, int q2, long long* ans) {
  int commonmultiple = lcm(q1, q2);

  ans[1] = commonmultiple;
  ans[0] = (long long)p1*commonmultiple/q1 + p2*commonmultiple/q2;
}

void multiplication(int p1, int q1, int p2, int q2, long long* ans) {
  ans[0] = p1*p2;
  ans[1] = q1*q2;
}