Salam, Codeforces! $$$\color{white}{\text{ «Be attentive about your thought that becomes your behavior» «Be attentive about your behavior that becomes your speech» «Be attentive about your speech because it becomes your habit»«Be attentive about your habit because it becomes your personality»«Be attentive about your personality because it becomes your destiny» Said by: Imam Ali}}$$$

We're so excited to invite you to take part in our round Harbour.Space Scholarship Contest 2023-2024 (Div. 1 + Div. 2) which will start on Aug/26/2023 17:35 (Moscow time). The round will be rated and open for everyone.

The problems were prepared and authored by amenotiomoi, Dhruvil Psychotic_D Kakadiya, Han wuhudsm Jinlong, Amir Hossein Amir_Parsa Farhadi, Matthew chromate00 Roh, JohnVictor, ODT, ugly2333, Lavine, RiverHamster, MagicalFlower and AquaMoon.

We would like to thank :

• irkstepanov for coordinating the round;
• aaaaawa, BurnedChicken, p_b_p_b and Sugar_fan for LGM testing;
• hibye1217, alireza_kaviani, errorgorn, JianfengZhu, AmShZ, Crying, Huah, bthero, fengzhengwei and Ecrade_ for GM and IGM testing;
• Kieray, k1r1t0, Arpa, triple__a, blxst, leukocyte, ITO and NemanjaSo2005 for M and IM testing;
• iiand, TAIYANGFENG, callmepandey, Mkswll and uuku for CM testing;
• adventofcode, KitasCraft, aayushdhankecha, Qualified, Nanani, USACOW and tllwtg for Expert testing;
• Hex-willappear, Savani004, AkibAzmain, Visrut_, Banis and Harshil4442 for Specialist testing;
• strange-creator for the only Pupil testing;
• Valenz for the only Newbie testing;
• MikeMirzayanov for the great Codeforces and Polygon platforms;
• And at last but not least, You for participaing in the round!

You will be given $$$9$$$ problems and $$$3$$$ hours to solve!

Score Distribution:

$$$500-1000-1250-1500-2000-2500-3000-3500-4250$$$

UPD1 : Editorial is out.

UPD2 :

First Solve

Top Performers

GL & HF ;)

This round wouldn't have been possible without Harbour.Space University's support.

This contest is for all interested eligible programmers who want to start their bachelor and master studies in Barcelona, Spain or Bangkok, Thailand, and join ICPC team.

For the next academic year (2023/24), Harbour.Space University is recruiting a fascinating community of competitive programmers from the top prize-winners of international Olympiads to join one of several competitive programming teams at the university.

In the next few years, their goal is to continue winning SWERC and competing at a high level in the ICPC globally. Therefore they want to invest a serious amount of energy, resources, and talent into these activities.

That’s why you are invited on an exciting journey in the company of like-minded people, outstanding coaches, and ongoing partnership Harbour.Space University with Codeforces.

Over 100 educational rounds were already organized, so the time has come to test our joint efforts and reward the most diligent.

Here’s what you win if you place in the contest:

The monthly living allowance throughout the entire duration of studies may vary depending on the overall performance of the students as measured by their GPA, professional achievements and official ICPC competition results. As a guideline, it is in the range of 700-1500 EUR (it might be applied to the contestants who win 4th-10th places).

No application fee is required for any of the awards listed above.

Good luck, and may the code be with you!

Hello, Codeforces!

First of all huge thanks to Dhruvil Psychotic_D Kakadiya for developing this great tool to help us growing our community.

Since many people like to see their unofficial rating changes in the contests they participate in gym, our team has developed a website that updates the rating of anyone who participates in our series of gym contests.

What is TheForces?

TheForces rounds are series of unofficial gym contests which are created by a group of CP lovers in the CF community with the purpose of contributing the Competitive Programming community.

What do you mean by rating changes?

From now on, You can see your performance and rating changes after each TheForces round on https://theforces.netlify.app.

UPD1: Change in style, and now users can find contest data of any other user by entering handle name.

UPD2: Now users can see the rating change graph below the contest data table of any user. Special thanks to wyhong3103 for his amazing tool (what-if-i-never-brick). He let me use his graph generating-script for this tool. Orz!

UPD3: Page not found error solved.

P.S : This is the initial version of the rating system and there will be more features in the next updates.

How does it calculate rating?

TheForces rating system is almost the same as Codeforces and it is using the same formulas that Codeforces uses to update the ratings, for more information about the rating changes, You can read this blog.

• TheForces Discord Server with more than 1000 members

• TheForces contests' archieve

Hello Codeforces!!

We're honored to invite you to TheForces Round #15 (Yummy-Forces) which will take place on Jun/05/2023 18:05 (Moscow time).

Don't forget the time, registration is open now!, sorry for the inconveniences, the problems are available + $$$5$$$ minutes extra time

You will have 2 hours and 15 minutes to solve 6 problems.

• Problems were prepared and authored by: k1r1t0, Amir_Parsa, O--O, Traverser_25.

• Also huge thanks to our ultrabig army of testers: physics0523, amenotiomoi, tyr0Whiz,wuhudsm, Little_Sheep_Yawn, k1r1t0, O--O, blxst, Madboly, absolute-mess, E404_Not_Found, ExpensiveAC, Believer., ashler66, Kev2103, parthtotalfun, EndlessDreams, BallBreaker, vikram108, Sarievo, yazan_istatiyeh, hkonvict, sai-17, Banis, _A7mad, LaVa_, yash_04.

• Also we want to thank You for participating in our rounds.

Discord Server (1000+ people, join for a cookie)

Contests' archive

Editorial

Hello Codeforces!!

We're honored to invite you to TheForces Round #14 (Cool-Forces) which will take place on May/23/2023 18:05 (Moscow time).

You will have $$$135$$$ minutes to solve $$$7$$$ problems.

Please don't forget the time. Registration is open now.

• Problems were prepared and authored by : amenotiomoi, Amir_Parsa, MrSavageVS, BallBreaker, repegfrost.

• Also huge thanks to our army of testers : tyr0Whiz, wuhudsm, Little_Sheep_Yawn, O--O, k1r1t0, blxst, Madboly, Virendra115, E404_Not_Found, ExpensiveAC, Abhishek_Srivastava, danish_droid, Muaath_5, Zen-Oh, Binary_Thinker.

• Also we want to thank you for participating in our rounds.

Discord Server (800+ people, join for a cookie )

Contests' archive

Editorial

Hello Codeforces!

Thanks for participating in the round, We hope you liked the problems!

Also huge thanks to EndlessDreams for preparing the editorial.

void elysia() {
   int n;cin >> n;
   if(n<1024ll) cout << n << "B" << endl; else
   if(n<1024ll*1024ll) cout << n/1024ll << "KiB" << endl; else
   if(n<1024ll*1024ll*1024ll) cout << n/1024ll/1024ll << "MiB" << endl; else
   if(n<1024ll*1024ll*1024ll*1024ll) cout << n/1024ll/1024ll/1024ll << "GiB" << endl;
}

void elysia() {
   int n,m;
   cin >> n >> m;
   cout << power(245,m,10)*n%10 << endl;
}

for _ in range(int(input())):
    n=int(input())
    s=0
    if bin(n)[2:]==bin(n)[2:][::-1]:
        s+=1        
    if str(n)==str(n)[::-1]:
        s+=1 
    if hex(n)[2:]==hex(n)[2:][::-1]:
        s+=1
    if s>=2:
        print("ghavi")
    else:
        print("fanni khordim")

#include<bits/stdc++.h>
using namespace std;
void solve()
{
	int n;
	cin>>n;
	vector<int> a(n+1),b(n+1),mp(n+1),f(n+1);
	for(int i=1;i<=n;i++){scanf("%d",&a[i]);mp[a[i]]=i;}
	for(int i=1;i<=n;i++){scanf("%d",&b[i]);f[i]=0x7fffffff;}
	int len=0;
	f[0]=0;
	for(int i=1;i<=n;i++)
	{
		int l=0,r=len,mid;
		if(mp[b[i]]>f[len])f[++len]=mp[b[i]];
		else 
		{
		while(l<r)
		{	
		    mid=(l+r)/2;
		    if(f[mid]>mp[b[i]])r=mid;
			else l=mid+1; 
		}
		f[l]=min(mp[b[i]],f[l]);
     	}
    }
    cout << 2*(n-len) << endl;
}
int main() {
   int T;cin >> T;
   while(T--) solve();
}

void elysia() {
   string t;cin >> t;
   if(t=="0") {
      cout << "YES" << endl;
      return;
   }
   if(t[0]=='0'||t.end()[-1]=='0'||(int)t.size()<=2) {
      cout << "NO" << endl;
      return;
   } else {
      t.pop_back();
      reverse(t.begin(),t.end());
      t.pop_back();
   }
   vector<int> Q;int sum=0;
   for(char i:t) sum+=i=='1';
   for(int i=0,cnt=0;i<(int)t.size();++i) {
      if(t[i]=='1') cnt++;
      if(t[i]=='0'||i==(int)t.size()-1) {
         if(cnt>sum/2) {
            cout << "NO" << endl;
            return;
         }
         cnt=0;
      }
   }
   cout << (sum%2==1?"NO":"YES") << endl;
}

#include<bits/stdc++.h>
using namespace std;
const int N = 1000010;
int n, sa[N], rk[N], oldrk[N << 1], id[N], key1[N], cnt[N];
 
bool cmp(int x, int y, int w) {
  return oldrk[x] == oldrk[y] && oldrk[x + w] == oldrk[y + w];
}
 
int main() {
  int i, m = 127, p, w ,n;
  string s;
  cin >> n >> s;
  n*=2;s+=s;
  
  for (i = 1; i <= n; ++i) ++cnt[rk[i] = s[i-1]];
  for (i = 1; i <= m; ++i) cnt[i] += cnt[i - 1];
  for (i = n; i >= 1; --i) sa[cnt[rk[i]]--] = i;
 
  for (w = 1;; w <<= 1, m = p) { 
    for (p = 0, i = n; i > n - w; --i) id[++p] = i;
    for (i = 1; i <= n; ++i)
      if (sa[i] > w) id[++p] = sa[i] - w;
 
    memset(cnt, 0, sizeof(cnt));
    for (i = 1; i <= n; ++i) ++cnt[key1[i] = rk[id[i]]];
 
    for (i = 1; i <= m; ++i) cnt[i] += cnt[i - 1];
    for (i = n; i >= 1; --i) sa[cnt[key1[i]]--] = id[i];
    memcpy(oldrk + 1, rk + 1, n * sizeof(int));
    for (p = 0, i = 1; i <= n; ++i)
      rk[sa[i]] = cmp(sa[i], sa[i - 1], w) ? p : ++p;
    if (p == n) {
      for (int i = 1; i <= n; ++i) sa[rk[i]] = i;
      break;
    }
  }
  for(int i=1;i<=n;++i)
     if(sa[i]<=n/2) {
        for(int j=sa[i];j<=n/2;++j) cout << s[j-1];
        for(int j=1;j<sa[i];++j) cout << s[j-1];
        return 0;
     }
  return 0;
}

// Code by blxst
#include <bits/stdc++.h>
#define int long long
#define fi first
#define se second
#define all(x) (x).begin(), (x).end()
 
using namespace std;
const int mod = 1e9 + 9;
const int key = 131;
int32_t main()
{
        ios_base::sync_with_stdio(false);
        cin.tie(NULL);
        int n;
        cin >> n;
        string s;
        cin >> s;
        s = s + s;
        s = '?' + s;
        vector<int> pre(2*n+5);
        int res = 0;
        for (int i = 1; i <= 2*n; i++) {
                res = (res*key + s[i])%mod;
                pre[i] = res;
        }
        vector<int> pow(2*n+5);
        pow[0] = 1;
        for (int i = 1; i <= 2*n; i++) {
                pow[i] = (pow[i-1] * key)%mod;
        }
        auto get = [&](int l, int r) {
                return (pre[r] - (pre[l-1]*pow[r - l + 1])%mod + mod)%mod;
        };
        auto comp = [&](int l1, int l2) {
                int lf = 1;
                int rg = n;
                int pos = 0;
                while (lf <= rg) {
                        int md = (lf + rg)/2;
                        if (get(l1, l1 + md - 1) == get(l2, l2 + md - 1)) {
                                pos = md;
                                lf = md + 1;
                        } else {
                                rg = md - 1;
                        }
                }
                if (s[l1 + pos] > s[l2 + pos]) return 1;
                else return 2;
        };
        int ans = 1;
        for (int i = 2; i <= n; i++) {
                if (comp(ans, i) == 1) ans = i;
        }
        cout << s.substr(ans, n) << '\n';
        return 0;
}

#define MOD 1000000007
int f[501][501],cntVII[502][502];
int dfs(int l,int r) {
   if(l==r+1) return 1;
   if(f[l][r]!=-1) return f[l][r];
   int sum=0;
   for(int i=l+1;i<=r;++i)
      if(a[l]>a[i]&&(i-l-1)%2==0)
         sum+=dfs(l+1,i-1)*dfs(i+1,r)%MOD*cntVII[(i-l+3)/2][(r-i)/2]%MOD;
   return f[l][r]=sum%MOD;
}
void elysia() {
   cin >> n;
   for(int i=1;i<=n;++i) cin >> a[i];
   for(int i=1;i<=n;++i)
      for(int j=1;j<=n;++j)
         f[i][j]=-1;
   cout << dfs(1,n) << endl;
}
signed main() {
   combi::init(10000,MOD);
   for(int i=1;i<=501;++i)
      for(int j=0;j<=501;++j)
         cntVII[i][j]=combi::C(i+j-1,i-1);
   ios_base::sync_with_stdio(0);
   cin.tie(0);cout.tie(0);
   elysia();
}

Hello, Codeforces!

We are happy to invite you to TheForces Round #13 (Boombastic-Forces), which will take place on May/07/2023 18:10 (Moscow time)

Editorial

You will have 120 minutes to solve 7 problems.

We strongly recommend you to read all problems.

• Problems were prepared and authored by Amir_Parsa ,E404_Not_Found, Sevawy.

• We would like to thank our army of testers: physics0523, Madboly, blxst, O--O, Virendra115, blxst, BallBreaker, ExpensiveAC, aphex, TheOpChicken123, leneza_41, EndlessDreams.

• Also we want to thank you for participating in our round.

Discord Server (700+ people)

Contests' archive

Hello Codeforces!!

As a member of TheForces team, We create gym rounds, As you all know WA on test 1 has 20 minutes penalty for unofficial contests (but in official rounds WA on test 1 doesn't have any penalty), And I see many contestants getting WA on test 1 and 20 minutes penalty which sometimes leads to lose the first place only because of that useless penalty, I kindly ask MikeMirzayanov or other headquarters to remove this feature, Thanks in advance.