poj2649 数论

 1 //Accepted    420K    16MS
 2 //考虑 0和n！    does not divide
 3 //      1和0！  divides
 4 #include <cstdio>
 5 #include <cstring>
 6 #include <iostream>
 7 using namespace std;
 8 const int imax_n = (1<<16)+5;
 9 int pri[imax_n];
10 int cnt;
11 void prime()
12 {
13     for (int i=2;i<imax_n;i++)
14     {
15         if ((long long )i*i<(long long )imax_n)
16         for (int j=i*i;j<imax_n;j+=i)
17         {
18             pri[j]=1;
19         }
20     }
21     cnt=0;
22     for (int i=2;i<imax_n;i++)
23     if (pri[i]==0)
24     pri[cnt++]=i;
25 }
26 int getNumber(int n,int k)
27 {
28     int ans=0;
29     if (k==0) return -1;
30     while (n>0)
31     {
32         ans+=n/k;
33         n/=k;
34     }
35     return ans;
36 }
37 int split(int n,int m)
38 {
39     int t;
40     //printf("n=%d\n",n);
41     if (n==0) return 0;
42     if (m==0)
43     {
44         if (n==1) return 1;
45         return 0;
46     }
47     for (int i=0;i<cnt && (__int64 )pri[i]*pri[i]<=(__int64 )n;i++)
48     {
49         if (n%pri[i]==0)
50         {
51             //printf("pri=%d\n",pri[i]);
52             t=0;
53             while (n%pri[i]==0)
54             {
55                 t++;
56                 n/=pri[i];
57             }
58             int temp=getNumber(m,pri[i]);
59             //printf("temp=%d t=%d\n",temp,t);
60             if (temp<t) return 0;
61         }
62     }
63     if (n!=1)
64     {
65         int temp=getNumber(m,n);
66         if (temp<1) return 0;
67     }
68     return 1;
69 }
70 int main()
71 {
72     prime();
73     int n,m;
74     while (scanf("%d%d",&n,&m)!=EOF)
75     {
76         int ans=split(m,n);
77         if (ans==1)
78         {
79             printf("%d divides %d!\n",m,n);
80         }
81         else
82         {
83             printf("%d does not divide %d!\n",m,n);
84         }
85     }
86     return 0;
87 }