hihocoder-1498-Diligent Robots

hihocoder-1498-Diligent Robots

 

#1498 : Diligent Robots

時間限制:10000ms

單點時限:1000ms

內存限制:256MB

描述

There are N jobs to be finished. It takes a robot 1 hour to finish one job.

At the beginning you have only one robot. Luckily a robot may build more robots identical to itself. It takes a robot Q hours to build another robot.  

So what is the minimum number of hours to finish N jobs?

Note two or more robots working on the same job or building the same robot won't accelerate the progress.

輸入

The first line contains 2 integers, N and Q.  

For 70% of the data, 1 <= N <= 1000000  

For 100% of the data, 1 <= N <= 1000000000000, 1 <= Q <= 1000

輸出

The minimum number of hours.

樣例輸入

10 1

樣例輸出

5

 

 

 

題解：

　　使用貪心算法的思想。

　　樣本複製以後須要去生產纔有效，因此機器人一定是先複製完。

　　還有一個想法是是否須要一邊複製一邊生產，這個想法是否認的，假如n生產m複製，獲得的是 m + (q+1）*n.  若是是一塊兒複製，則獲得的是 (m + n)*q , 大於前者。

 

 

#include <cstdio> 
#include <cstdlib> 

int main()
{
    int q; 
    long long cnt, n, k; 
    while(scanf("%lld %d", &n, &q) != EOF)
    {
        cnt = 0; 
        k = 1; 
        while(2*q*k < n)
        {
            k *= 2; 
            cnt += q; 
        }
        cnt += n / k; 
        if(n%k != 0)
        {
            cnt += 1; 
        }
        printf("%lld\n", cnt );
    }
    return 0; 
}