message(s) / RUNNING
Source code
#include <iostream>
#include <vector>

using namespace std;

int main(){
	unsigned int n,m,t=0,p=1,f=0;
	int k,l=10;
	vector<unsigned int> ost;
	vector<unsigned int> otv;
	cin>>n>>m;
	k=m;
	while(k!=0){
		f++;
		k/=10;
	}
//	cout<<f<<endl;
	ost.push_back(n);
	while(t==0){
		n*=10;
		while(n<m){
			otv.push_back(0);
			ost.push_back(n);
			n*=10;
		}
		ost.push_back(n%m);
		otv.push_back(n/m);
		n=n%m;
//		cout<<"("<<n<<")";
		for(int  j=0;(j<ost.size()-1)&&(j<f+2);j++){
//			cout<<n<<" "<<ost[j]<<" "<<j<<endl;
			if(n==ost[j]){
				t=1;
				p=j;
//				cout<<p<<" "<<ost[p]<<" "<<n<<endl;
				break;
			}
		}
		if(n==0){
			t=2;
			break;
		}

	}
//	cout<<p<<" "<<otv[otv.size()-1]<<endl;
	cout<<"0.";
	if(t==1){
		for(unsigned int i=0;i<p;i++){
			cout<<otv[i];
		}
		cout<<"(";
		for(auto i=p;i<otv.size();i++){
			cout<<otv[i];
		}
		cout<<")";
	}
	if(t==2){
		for(unsigned int i=0;i<otv.size();i++){
			cout<<otv[i];
		}
	}

	return 0;
}