題目連結：http://115.28.203.224/problem.php?cid=1010&pid=35

題目描述

一個正整數如果等於組成它的各位數字的階乘之和，該整數稱為階乘和數。
例如，145=1!+4!+5!，則145是一個三位階詳細和數。
請問:共有多少個階乘和數？ 資料範圍 1<=x <= 1e7

輸入

輸出

所有的階乘和數(按字典序，即1打頭的在前，2打頭的次之,..., 空格分隔)

提示

資料範圍 1<=x<=1e7

程式碼

 1 #include <iostream>
 2 using namespace std;
 3 long fac(int
 
 n)
 4 {
 5     long sum = 1;
 6     for(int i = 1; i <= n; i++)
 7         sum *= i;
 8     return sum;
 9 }
10 int main()
11 {
12     long m1, m2, m3, m4, m5, m6, n1, n2, n3, n4, n5, n6;
13     for(int a = 1; a <= 9; a++)
14     {
15         if (a == fac(a))
16             cout<<a<<"
 
 ";
17         for(int b = 0; b <= 9; b++)
18         {
19             m1 = a * 10 + b;
20             n1 = fac(a) + fac(b);
21             if (m1 == n1)
22                 cout<<m1<<" ";
23             for(int c = 0; c <= 9; c++)
24             {
25                 m2 = m1 * 10 + c;
26
 
                 n2 = n1 + fac(c);
27                 if (m2 == n2)
28                     cout<<m2<<" ";
29                 for(int d = 0; d <= 9; d++)
30                 {
31                     m3 = m2 * 10 + d;
32                     n3 = n2 + fac(d);
33                     if(m3 == n3)
34                         cout<<m3<<" ";
35                     for(int e = 0; e <= 9; e++)
36                     {
37                         m4 = m3 * 10 + e;
38                         n4 = n3 + fac(e);
39                         if(m4 == n4)
40                             cout<<m4<<" ";
41                         for(int f = 0; f <= 9; f++)
42                         {
43                             m5 = m4 * 10 + f;
44                             n5 = n4 + fac(f);
45                             if(m5 == n5)
46                                 cout<<m5<<" ";
47                             for(int g = 0;g <= 9; g++)
48                             {
49                                 m6 = m5 * 10 + g;
50                                 n6 = n5 + fac(g);
51                                 if(m6 == n6)
52                                     cout<<m6<<" ";
53                             }
54                         }
55                     }
56                 }
57             }
58         }
59     }
60     return 0;
61 }