Make it Divisible || Problem Code: MAKEDIV3 || codechef starters 12

Given an integer N$N$, help Chef in finding an N$N$-digit odd positive integer$\mathbf{\text{odd positive integer}}$ X$X$ such that X$X$ is divisible by 3$3$ but not by 9$9$.

Note:$\mathbf{\text{Note}}:$ There should not be any leading zeroes in X$X$. In other words, 003$003$ is not a valid 3$3$-digit odd positive integer.

Input Format

• The first line of input contains a single integer T$T$, denoting the number of testcases. The description of the T$T$ testcases follows.
• The first and only line of each test case contains a single integer N$N$, denoting the number of digits in X$X$.

Output Format

For each testcase, output a single line containing an N$N$-digit odd positive integer X$X$ in decimal number system, such that X$X$ is divisible by 3$3$ but not by 9$9$.

Sample Input 1

3

1

2

3

Sample Output 1

3

15

123

Solution: 

 #include<bits/stdc++.h>

using namespace std;

void solve(){

    long int n;

    cin>>n;

    vector<int> var(n, 3);

    if(n%3 == 0){

        var[n-1] = 1;

        var[n-2] = 2;

    }

    for (int i = 0; i < n; i++)

    {

        cout<<var[i];

    }

    cout<<endl;

}

int main(){

    int t;

    cin>>t;

    while (t--)

    {

        solve();

    }

    return 0;

}