Day 9.7

 1 #include <cstdio>
 2 #include <cstring>
 3 char s[100010];
 4 int a[200010],n,maxlen=0,ans,len,start,flag=0;
 5 int main()
 6 {
 7     freopen("beads.in","r",stdin);
 8     freopen("beads.out","w",stdout);
 9     scanf("%s",s);n=strlen(s);
10     for (int i=1;i<=n;i++) a[n+i]=a[i]=s[i-1]-‘0‘;
11     len=0;
12     for (int i=1;i<=2*n;i++)
13     {
14         if (a[i]!=2&&a[i]!=3) len=0;
15         if (a[i]==2) len=1,start=i;
16         if (len&&a[i]==3) len++;
17         if (len>maxlen) maxlen=len,ans=start,flag=1;
18     }
19     len=0;
20     for (int i=2*n;i>=1;i--)
21     {
22         if (a[i]!=2&&a[i]!=3) len=0;
23         if (a[i]==2) len=1,start=i;
24         if (len&&a[i]==3) len++;
25         if (len>maxlen) maxlen=len,ans=start,flag=2;
26     }
27     if (flag==0)
28     {
29         printf("TvT");
30     }
31     if (flag==1)
32     {
33         printf("2");
34         while(a[++ans]==3) printf("3");
35     }
36     if (flag==2)
37     {
38         printf("2");
39         while(a[--ans]==3) printf("3");
40     }
41 }

 1 #include <cstdio>
 2 #include <iostream>
 3 #define ll long long
 4 using namespace std;
 5 ll n,k,p,w=1,sy[1000000],flag=0;
 6 ll powx(ll k)
 7 {
 8     if (k==0) return 1;
 9     ll s=powx(k/2);
10     s=s*s%p;
11     if (k%2==1) s=s*2%p;
12     return s;
13 }
14 int main()
15 {
16     freopen("rabit.in","r",stdin);
17     freopen("rabit.out","w",stdout);
18     ios::sync_with_stdio(false);
19     cin>>n>>k>>p;
20     for (int i=0;i<k-1&&i<=n;i++)
21     {
22         w=w*2%k;
23         if (w==1)
24         {
25             flag=i;
26             break;
27         }
28         if (sy[w]==1) break;
29         sy[w]=1;
30     }
31     if (flag)
32         cout<<(powx(flag+1)-1+p)%p*powx(n-flag)%p<<endl;
33     else
34         cout<<powx(n+1)<<endl;
35 }