Form_number_divisible_by_3.cpp

#include <iostream>
#include<vector>

using namespace  std;

void computeNumberFromSubarray(vector<int> arr,int k){

	pair<int,int> ans;

	int sum=0;

	for (int i = 0; i <k; i++)
	{
		sum+=sum+arr[i];
	}

	bool found=false;

	if(sum%3==0){
		ans=make_pair(0,k-1);
		found=true;
	}

	for (int j=k; j <arr.size(); j++)
	{
		if(found){
			break;
		}

		sum+=sum+arr[j]-arr[j-k];
		if(sum%3==0){
			ans=make_pair(j-k+1,j);
			found=true;
		}
 
	}

	if(!found){
		ans=make_pair(-1,0);
	}

	if(ans.first==-1){
		cout<<"No such subarray"<<endl;
	}

	else{

		for (int i = ans.first; i <= ans.second; i++)
		{
			cout<<arr[i]<<" ";
			
		}

	}

}



int main(){

	vector<int> arr={84,23,45,12,56,82};

	int k=3;

	computeNumberFromSubarray(arr,3);

	return 0;
}