2013
12-12

# A C

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 .

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)

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.

2
A 10 10
C 4 2

3628800
6

2011-12-16 01:50:33

# include <stdio.h>

int factorial[15] = {1, 1} ;

int main ()
{
int i, T, a, b ;
char ch ;
for(i = 2 ; i <= 10 ; i++)
factorial[i] = factorial[i-1] * i ;
scanf ("%d%*c", &T) ;
while (T--)
{
scanf ("%c %d %d%*c", &ch, &a, &b) ;
if (ch == 'A') printf ("%d\n", factorial[a] / factorial[a-b]) ;
else printf ("%d\n", factorial[a] / factorial[b] / factorial[a-b]) ;
}
return 0 ;
}