HDU 6159 cable cable cable

最新推荐文章于 2019-08-09 19:30:51 发布

原创最新推荐文章于 2019-08-09 19:30:51 发布 · 356 阅读

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本文探讨了如何通过最少数量的电缆将不同颜色信号源连接到选定的显示屏上，确保每个显示屏显示不同的颜色。提出了一个简洁的数学公式来解决该问题。

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cable cable cable

Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 0 Accepted Submission(s): 0

Problem Description

Connecting the display screen and signal sources which produce different color signals by cables, then the display screen can show the color of the signal source.Notice that every signal source can only send signals to one display screen each time.
Now you have

M display screens and

K different signal sources(

K≤M≤232−1). Select

K display screens from

M display screens, how many cables are needed at least so that **any**

K display screens you select can show exactly

K different colors.

Input

Multiple cases (no more than

100), for each test case:
there is one line contains two integers

M and

Output

Output the minimum number of cables

Sample Input

3 2
20 15

Sample Output

4
90
Hint

As the picture is shown, when you select M1 and M2, M1 show the color of K1, and M2 show the color of K2.

When you select M3 and M2, M2 show the color of K1 and M3 show the color of K2.

When you select M1 and M3, M1 show the color of K1.