blob: a0020f6b450a1606e92359a3c02a2aa77651ac9d (
plain)
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 <stdio.h>
#include <string.h>
#define MAXTERM 3000000
int next[MAXTERM];
const int factorial[10] = {1, 1, 2, 6, 24, 120, 720, 5040, 40320, 362880};
int sum_fact_digits(int n)
{
int sum = 0;
while (n > 0) {
sum += factorial[n%10];
n /= 10;
}
return sum;
}
void init()
{
memset(next, 0, sizeof(next));
for (int i = 1; i < 1000000; i++) {
if (next[i])
continue;
next[i] = sum_fact_digits(i);
for (int j = next[i]; next[j] == 0; j = next[j]) {
next[j] = sum_fact_digits(j);
}
}
}
int chainlen(int n)
{
int chain[100], L = 0;
while (1) {
for (int i = 0; i < L; i++) {
if (chain[i] == n)
return L;
}
chain[L] = n;
L++;
n = next[n];
}
}
int main()
{
int count = 0;
init();
for (int i = 1; i <= 1000000; i++) {
if (chainlen(i) == 60)
count++;
}
printf("%d\n", count);
}
|