1 #include<cstdio>

 2 #include<cstdlib>

 3 #include<cstring>

 4 #include<iostream>

 5 using namespace std;

 6 #define M 100010

 7 #define D 1010

 8

 9 bool np[M/10];

10 int pri[M/20];

11 int cnt;

12

13 int mmin(int x,int y) {return x<y?x:y;}

14 void init_pri()

15 {

16     cnt=0;

17     memset(np,false,sizeof(np));

18     for (int i=2;i<=M/10;i++)

19     {

20       if (!np[i]) pri[++cnt]=i;

21       for (int j=1;j<=cnt&&i*pri[j]<=M/10;j++)

22       {

23         np[i*pri[j]]=true;

24         if (i%pri[j]==0) break;//不能调到前一句前

25       }

26     }

27     /*2

28     cnt=0;

29     memset(np,false,sizeof(np));

30     for (int i=2;i<=M/10;i++)

31     {

32       if (np[i]) continue;

33       pri[++cnt]=i;

34       for (int j=2;i*j<=M/10;j++)

35         np[i*j]=true;

36     }

37     */

38 }

39 int main()

40 {

41     init_pri();

42     while (1)

43     {

44       int m,x,y;

45       scanf("%d%d%d",&m,&x,&y);

46       if (m+x+y==0) break;

47       int pp,qq; pp=qq=0;

48       for (int i=1;i<=cnt;i++)

49       {

50         int p=pri[i],lim=mmin(y*p/x,m/p);

51         int tmp=i;

52         for (int j=12;j>=0;j--)

53           if (tmp+(1<<j)<=cnt && pri[tmp+(1<<j)]<=lim) tmp+=(1<<j);

54         if (tmp==i && p*pri[tmp]>m) break;//上面的位调整没有一次成功，这时可能就单乘也是不合法的

55         int q=pri[tmp];

56         if (p*q>pp*qq) pp=p,qq=q;

57       }

58       printf("%d %d\n",pp,qq);

59     }

60     return 0;

61 }

62  快

 1 #include<cstdio>

 2 #include<cstdlib>

 3 #include<cstring>

 4 #include<iostream>

 5 using namespace std;

 6 #define M 100000

 7 #define N 1000

 8 typedef long long LL;

 9

10 int pr=0;

11 LL mn_prim[M+10],prim[M+10];

12

13 void get_prime()

14 {

15     memset(mn_prim,0,sizeof(mn_prim));//最小质因子

16     for (LL i=2;i<=M;i++)

17     {

18       if (!mn_prim[i]) prim[++pr]=i;

19       for (int j=1;j<=pr;j++)

20       {

21         if (prim[j]*i>M) break;

22         mn_prim[prim[j]*i]=prim[j];

23         if (i%prim[j]==0) break;//

24       }

25     }

26 }

27 int main()

28 {

29     LL m,a,b;

30     get_prime();

31     while (1)

32     {

33       scanf("%lld%lld%lld",&m,&a,&b);

34       if (!m&&!a&&!b) break;

35       LL tp=0,tq=0;

36       for (int i=1;i<=pr;i++)

37       {

38         LL p,qq=0;

39         p=prim[i];

40         int l=i,r=pr;

41         while (l<=r)

42         {

43           int mid=(l+r)>>1;

44           LL q=prim[mid];

45           if (p*q>m || a*q>b*p) r=mid-1;//相乘会超出int范围

46           else qq=q,l=mid+1;

47         }

48         if (p*qq>tp*tq) tp=p,tq=qq;

49       }

50       printf("%lld %lld\n",tp,tq);

51     }

52     return 0;

53 }