UVAOJ 568 基础题 阶乘 数论

http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=509
  Just the Facts 

The expression N!, read as ``N factorial," denotes the product of the first N positive integers, where N is nonnegative. So, for example,

 

N N!
0 1
1 1
2 2
3 6
4 24
5 120
10 3628800

For this problem, you are to write a program that can compute the last non-zero digit of any factorial for ( $0 \le N \le 10000$). For example, if your program is asked to compute the last nonzero digit of 5!, your program should produce ``2" because 5! = 120, and 2 is the last nonzero digit of 120.

 

Input 

Input to the program is a series of nonnegative integers not exceeding 10000, each on its own line with no other letters, digits or spaces. For each integer N, you should read the value and compute the last nonzero digit of N!.

 

Output 

For each integer input, the program should print exactly one line of output. Each line of output should contain the value N, right-justified in columns 1 through 5 with leading blanks, not leading zeroes. Columns 6 - 9 must contain `` -> " (space hyphen greater space). Column 10 must contain the single last non-zero digit of N!.

 

Sample Input 

1
2
26
125
3125
9999

 

Sample Output 

    1 -> 1
    2 -> 2
   26 -> 4
  125 -> 8
 3125 -> 2
 9999 -> 8

 

 

Miguel A. Revilla 
1998-03-10
 1 /*************************************************************************
 2     > File Name: 12345.cpp
 3     > Author: acmicpcstar
 4     > Mail: acmicpcstar@gmail.com
 5     > Created Time: 2014年04月24日 星期四 11时46分18秒
 6  ************************************************************************/
 7 
 8 #include<iostream>
 9 #include<string>
10 #include<cstdio>
11 #include<cmath>
12 #include<algorithm>
13 using namespace std;
14 const double pi=atan(1.0)*4.0;
15 int main()
16 {long long  n,sum,i;
17 while(cin>>n)
18 {sum=1;
19  for(i=2;i<=n;i++)
20  {sum=sum*i;
21  while(sum%10==0)  sum/=10;
22  sum=sum%1000000000;
23  }
24 printf("%5d -> %d\n",n,sum%10);
25 }
26 return 0;
27 }

开始就保留了1位数字%10。。。结果发现会数据丢失。。。3125。。。后来COld。H说保留10位。。。。为了不溢出用了long long。。。网上说。。。5位就够了～哈哈～

 

posted @ 2014-04-24 21:05  acmicpcstar  阅读(165)  评论(0)  编辑  收藏  举报