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)
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.
Sample Input 2 A 10 10 C 4 2
Sample Output 3628800 6
题意：很简单，看图片就能理解了。 水题一个！就不多解释了。
代码语言：javascript复制import java.util.Scanner;
public class Main{
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int t = sc.nextInt();
while(t-->0){
String str = sc.next();
int n = sc.nextInt();
int m =sc.nextInt();
if(str.charAt(0)=='A'){
System.out.println(a(n,m));
}else{
System.out.println(c(n,m));
}
}
}
private static int c(int n, int m) {
int num =1;
if(n-m>m){
m=n-m;
}
int cnum=1;
for(int i=1;i<=n-m;i ){
cnum=cnum*i;
}
for(int i=m 1;i<=n;i ){
num=num*i;
}
return num/cnum;
}
private static int a(int n, int m) {
int num=1;
for(int i=n-m 1;i<=n;i ){
num=num*i;
}
return num;
}
}
