http://acm.hdu.edu.cn/showproblem.php?pid=1570
A C
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 3391 Accepted Submission(s): 2179
Problem Description
Are you excited when you see the title "AC" ? If the answer is YES , AC it ;
You must learn these two combination formulas in the school . If you have forgotten it , see the picture.
Now I will give you n and m , and your task is to calculate the answer .
Input
In the first line , there is a integer T indicates the number of test cases.
Then T cases follows in the T lines.
Each case contains a character 'A' or 'C', two integers represent n and m. (1<=n,m<=10)
Then T cases follows in the T lines.
Each case contains a character 'A' or 'C', two integers represent n and m. (1<=n,m<=10)
Output
For each case , if the character is 'A' , calculate A(m,n),and if the character is 'C' , calculate C(m,n).
And print the answer in a single line.
And print the answer in a single line.
Sample Input
2 A 10 10 C 4 2
Sample Output
3628800 6
AC code：
#include <iostream>
using namespace std;
int main()
{
char c;
int n,m,i,s1,s2,s3,t;
cin>>t;
while(t--)
{
cin>>c>>n>>m;
s1=1;
s2=1;
s3=1;
for(i=1;i<=n;i++)
s1*=i;
for(i=1;i<=n-m;i++)
s2*=i;
if(c=='A')
{
cout<<s1/s2<<endl;
}
else if(c=='C')
{
for(i=1;i<=m;i++)
s3*=i;
cout<<s1/s2/s3<<endl;
}
}
return 0;
}