UVa 332 - Rational Numbers from Repeating Fractions

Accepted date: 2012-11-29
Ranking (as of 2013-01-19): 24
Language: C++

/*
  UVa 332 - Rational Numbers from Repeating Fractions

  To build using Visucal Studio 2008:
    cl -EHsc -O2 UVa_332_Rational_Numbers.cpp
*/

#include <cstdio>
#include <cstdlib>
#include <cstring>

int gcd(int x, int y)
{
  if (x < y)
    return gcd(y, x);
  else
      return y == 0 ? x : gcd(y, x % y);
}

int main()
{
  const int nr_digits_max = 9;
  const int pow_10s[nr_digits_max + 1] = {
    1, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000, 1000000000
  };
  for (int case_nr = 1; ; case_nr++) {
    int j;
    scanf("%d", &j);
    if (j == -1)
      break;
    char s[nr_digits_max + 3];
    scanf("%s", s);
    int k = strlen(s + 2) - j;
    int n = static_cast<int>(strtol(s + 2, NULL, 10));
    int numerator, denominator;
    if (j) {
      numerator = n - n / pow_10s[j];
      denominator = pow_10s[k + j] - pow_10s[k];
    }
    else {
      numerator = n;
      denominator = pow_10s[k];
    }
    int g = gcd(numerator, denominator);
    printf("Case %d: %d/%d\n", case_nr, numerator / g, denominator / g);
  }
  return 0;
}