Count Number of binary strings

#1

#include
using namespace std;
int countstring(int n)
{
int arr[2][100];
arr[0][0]=1;
arr[1][0]=1;
for(int i=1;i<91;i++)
{
for(int j=0;j<2;j++)
{
if(j==0)
arr[j][i]=arr[j][i-1]+arr[j+1][i-1];
if(j==1)
arr[j][i]=arr[j-1][i-1];

	}
}
return arr[0][n];

}
int main() {
int t;
cin>>t;
while(t–)
{
int n;
cin>>n;
cout<<countstring(n)<<endl;
}
return 0;
}

#2

@mvikas545
you have to use long long, since this values becomes very large.

#3

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