USACO 2.4 Fractions To Decimals

#include <algorithm>
#include <vector>
#include <iostream>
#include <fstream>
#include <utility>
#include <cmath>
#include <string>
#include <unordered_map>
#include <sstream>

using namespace std;

int N, D;
int outCnt = 1;
void format(ofstream &output) {
  ++outCnt;
  if (outCnt == 76) {
    output << endl;
    outCnt = 0;
  }
}

int main() {
  ifstream fin("fracdec.in");
  ofstream fout("fracdec.out");
  fin >> N >> D;
  
  ostringstream os;
  int d = N / D;
  fout << N / D;
  while (d / 10) {
    ++outCnt;
    d %= 10;
  }
  int r = N % D;
  
  if (!r) {
    fout << ".0" << endl;
    outCnt += 2;
    return 0;
  } else {
    fout << ".";
    ++outCnt;
  }
  
  vector<int> ds;
  unordered_map<int, int> map;
  
  while (r && map.find(r) == map.end()) {
    map[r] = (int)ds.size();
    r *= 10;
    ds.push_back(r / D);
    r %= D;
  }
  
  if (r) {
    for (int i = 0; i < map[r]; ++i) {
      fout << ds[i]; format(fout);
    }
    
    fout << "("; format(fout);
    
    for (int i = map[r]; i < ds.size(); ++i) {
      fout << ds[i]; format(fout);
    }
    
    fout << ")"; format(fout);
  } else {
    for (int i = 0; i < ds.size(); ++i) {
      fout << ds[i]; format(fout);
    }
  }
  
  fout << endl;
  return 0;
}