#include<iostream>
using namespace std;
int main()
{
int N;
cin>>N;
while(N--)
{
int WholeN,k,ciga;
cin>>WholeN>>k;
ciga=WholeN;
while(WholeN/k>0)
{
ciga+=WholeN/k;
WholeN=WholeN%k+WholeN/k;
}
cout<<ciga<<endl;
}
}
思想很简单，一次抽完所有烟，然后换新的烟，将留下的没有换的烟蒂和再次抽剩下的烟蒂相加再去换，直到无法再换原文：http://blog.csdn.net/jingweihu/article/details/25294045