Codeforces Round #640 (Div. 4)C. K-th Not Divisible by n

Problem description

You are given two positive integers n and k. Print the k-th positive integer that is not divisible by n.
For example, if n=3, and k=7, then all numbers that are not divisible by 3 are: 1,2,4,5,7,8,10,11,13…. The 7-th number among them is 10.

Input

The first line contains an integer t (1≤t≤1000) — the number of test cases in the input. Next, t test cases are given, one per line.
Each test case is two positive integers n (2≤n≤109) and k (1≤k≤109).

Output

For each test case print the k-th positive integer that is not divisible by n.

Example

input
6
3 7
4 12
2 1000000000
7 97
1000000000 1000000000
2 1
output
10
15
1999999999
113
1000000001
1

枚举会超时，所以考虑找规律。

#include 
#include 
typedef long long ll;
using namespace std;
int main()
{
    ll T,n,k,c,ans;
    cin>>T;
    while(T--)
    {
        cin>>n>>k;
        c=n-1;//每n个数里，不能被n整除的数有n-1个
        if(k%c==0)
            ans=n*(k/c)-1;
        else
            ans=n*(k/c)+k%c;
        cout<<ans<<endl;
    }
    return 0;
}