題目:
https://onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=7&page=show_problem&problem=509
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
| #include <iostream>
#include <vector>
#include <algorithm>
#include <string>
using namespace std;
void multiply(vector<int> &v, int n){
int carry = 0;
for(int i=0; i<v.size(); ++i){
int product = v[i] * n + carry;
v[i] = product % 10;
carry = product / 10;
}
while(carry > 0){
v.push_back(carry%10);
carry /= 10;
}
return;
}
string factorial(int n){
if(n == 0) return "1";
vector<int> v = {1};
for(int i=2; i<=n; ++i){
multiply(v, i);
}
string result = "";
for(size_t i=0; i<v.size(); ++i){
result += to_string(v[i]);
}
return result;
}
int main(){
string str;
int n;
while(cin >> n){
str.clear();
str = factorial(n);
while(str[0] == '0'){
str.erase(str.begin(), str.begin()+1);
}
cout.width(5);
cout << n;
cout << " -> " << str[0] << '\n';
}
return 0;
}
|
