URAL 1083. Factorials!!! （阅读理解）
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1083. Factorials!!! Time limit: 1.0 second
Memory limit: 64 MB
Definition 1.
n!!…! =
n(
n?
k)(
n?2
k)…(
n mod
k), if
k doesn’t divide
n;
n!!…! =
n(
n?
k)(
n?2
k)…
k, if
k divides
n (There are
k marks ! in the both cases).
Definition 2.
X mod
Y — a remainder after division of
X by
Y. For example, 10 mod 3 = 1; 3! = 3·2·1; 10!!! = 10·7·4·1. Given numbers
n and
k we have calculated a value of the expression in the first definition. Can you do it as well?
Input contains the only line: one integer
n, 1 ≤
n ≤ 10, then exactly one space, then
k exclamation marks, 1 ≤
k ≤ 20.
Output contains one number —
n!!…! (there are
k marks ! here).
Sample
Problem Author: Oleg Katz
Problem Source: The 3rd high school children programming contest, USU, Yekaterinburg, Russia, March 4, 2001
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解析：直接按题目中的定义计算即可。
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AC代码：
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#include
using namespace std;
int main(){
int n;
string s;
while(~scanf("%d", &n)){
cin>>s;
int k = s.size();
int ans = 1;
if(n % k){
int t = n / k;
for(int i=0; i<=t; i++){
ans *= (n - i * k);
}
}
else{
int t = n / k - 1;
for(int i=0; i<=t; i++){
ans *= (n - i * k);
}
}
printf("%d\n", ans);
}
return 0;
}
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