hdu6195 cable cable cable

Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 2084 Accepted Submission(s): 1348

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

display screens and

different signal sources(

). Select

display screens from

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

display screens you select can show exactly

different colors.

Input

Multiple cases (no more than

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

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.

Statistic | Submit | Clarifications | Back

题意：给出m个显示屏和k个信号，要求任选k个显示屏都可以显示所有的信号

思路：找规律

#include <iostream>

using namespace std;
typedef long long ll;
int main()
{
   ll m,k;
   while(cin>>m>>k)
   {


   ll tmp=m-(k+1);
   cout<<k*2+tmp*k<<endl;
   }
    return 0;
}