November 2012 Bronze Problem 1: Find the Cow!

The contest has ended! I have posted the first solution now.
Result: 9/10 *********t (timeout)
cowfind.cpp

#include <iostream>
#include <fstream>
#include <string>

#define loopi(x) loopi_start(x,0)
#define loopi_start(x,s) for(int i = (s); i < (x); ++i)
#define loop_rev(a,x,stop) for(int a = (x); a >= (stop); --a)

using namespace std;

int main() {
 ofstream fout ("cowfind.out");
 ifstream fin("cowfind.in");
 // get input
 string str;
 fin >> str;
 int locations = 0;
 //)((()())())
 loopi(str.length() - 3){
  if(str[i] == '(' && str[i + 1] == '('){
   loop_rev(j, str.length() - 1, i + 3){
    if(str[j] == ')' && str[j - 1] == ')')
     ++locations;
   }
  }
 }
 // output
 fout << locations << '\n';
 // cleanup
 fin.close();
 fout.close();
 return 0;
}