阶乘新问题-题解(C语言代码)

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这题的原理其实看阶乘的答案，就能看出一些规律。就是0的出现和多少，与5和5的倍数有密切关系。
1! = 1
2! = 2
3! = 6
4! = 24
5! = 120
6! = 720
7! = 5040
8! = 40320
9! = 362880
10! = 3628800
11! = 39916800
12! = 479001600
13! = 6227020800
14! = 87178291200
15! = 1307674368000
16! = 20922789888000
17! = 355687428096000
18! = 6402373705728000
19! = 121645100408832000
20! = 2432902008176640000
21! = 51090942171709440000
22! = 1124000727777607680000
23! = 25852016738884976640000
24! = 620448401733239439360000
25! = 15511210043330985984000000
26! = 403291461126605635584000000
27! = 10888869450418352160768000000
28! = 304888344611713860501504000000
29! = 8841761993739701954543616000000
30! = 265252859812191058636308480000000
31! = 8222838654177922817725562880000000
32! = 263130836933693530167218012160000000
33! = 8683317618811886495518194401280000000
34! = 295232799039604140847618609643520000000
35! = 10333147966386144929666651337523200000000
36! = 371993326789901217467999448150835200000000
37! = 13763753091226345046315979581580902400000000
38! = 523022617466601111760007224100074291200000000
39! = 20397882081197443358640281739902897356800000000
40! = 815915283247897734345611269596115894272000000000
41! = 33452526613163807108170062053440751665152000000000
42! = 1405006117752879898543142606244511569936384000000000
43! = 60415263063373835637355132068513997507264512000000000
44! = 2658271574788448768043625811014615890319638528000000000
45! = 119622220865480194561963161495657715064383733760000000000
46! = 5502622159812088949850305428800254892961651752960000000000
47! = 258623241511168180642964355153611979969197632389120000000000
48! = 12413915592536072670862289047373375038521486354677760000000000
49! = 608281864034267560872252163321295376887552831379210240000000000
50! = 30414093201713378043612608166064768844377641568960512000000000000

```c
#include<stdio.h>

int main(void)
{
    int i = 0,j =0,a =0;
 	long int n;
 long int num = 0;
	scanf("%ld",&n);
	for(i = 1;i <= n;i++)
	{    
	     j = i;
	     a = 0;
	     while(j % 5 == 0)
	    {
	        j/=5;
	        a++;
	    } 
	   num += (n-i+1) * a;
	}	
	printf("%ld",num);
	
}

```

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本文分类：题解列表
浏览次数：700 次浏览
发布日期：2020-01-05 12:40:42
本文链接：https://blog.dotcpp.com/a/64494

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阶乘新问题-题解(C语言代码)

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阶乘新问题-题解(C语言代码)

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