ILSMATH - Đếm số giai thừa !
Tác giả: ll931110
Ngôn ngữ: C++
//#pragma comment(linker, "/STACK:16777216")
#include <algorithm>
#include <bitset>
#include <cmath>
#include <ctime>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <deque>
#include <fstream>
#include <functional>
#include <iostream>
#include <map>
#include <set>
#include <sstream>
#include <stack>
#include <queue>
#include <vector>
#include <utility>
#define pi acos(-1.0)
using namespace std;
int n;
int main()
{
// freopen("ils.in","r",stdin);
// freopen("ils.ou","w",stdout);
scanf("%d", &n);
vector<int> ret;
if (n == 1) ret.push_back(0);
for (int i = 1; ; i++)
{
int val = (int) trunc( 0.5 * log10(2 * pi * i) + 1.0 * i * log10(1.0 * i / exp(1.0)) );
if (val > n - 1) break;
if (val == n - 1) ret.push_back(i);
}
if (ret.empty()) printf("NO\n"); else
{
printf("%d\n", ret.size());
for (int i = 0; i < ret.size(); i++) printf("%d\n", ret[i]);
}
}