Good Bye 2013 A

A. New Year Candles

time limit per test
1 second

memory limit per test
256 megabytes

input
standard input

output
standard output

Vasily the Programmer loves romance, so this year he decided to illuminate his room with candles.

Vasily has a candles.When Vasily lights up a new candle, it first burns for an hour and then it goes out. Vasily is smart, so he can make b went out candles into a new candle. As a result, this new candle can be used like any other new candle.

Now Vasily wonders: for how many hours can his candles light up the room if he acts optimally well? Help him find this number.

Input
The single line contains two integers, a and b (1 ≤ a ≤ 1000; 2 ≤ b ≤ 1000).

Output
Print a single integer — the number of hours Vasily can light up the room for.

Sample test(s)

input

4 2

output

7

input

6 3

output

8

Good Bye 2013

很经典的面试试题。

#include <iostream>
#include <stdio.h>
#include <string>
#include <string.h>
#include <algorithm>
#include <stdlib.h>
#include <vector>
using namespace std;
typedef long long LL ;
int b ;

int dfs(int well ,int burn){
if(well == 0 && burn < b)
return 0 ;
int sum = well ;
int next_well = burn/b ;
burn %= b ;
return sum + dfs(next_well,well+burn) ;
}

int main(){
int a ;
cin>>a>>b ;
cout<<dfs(a,0)<<endl ;
return 0 ;
}