Since GPT-5 solved all the problems in the ICPC World Final, it seems that many competitive programming training platforms have started banning the use of AI.

Still, I hope I can achieve good results in upcoming contests — and wish everyone the best of luck in reaching their own goals too

Now we have significant changes for the rule against generative AI. Not only ABC, but ARC and AGC are also affected. I suggest reading the new rules for all AtCoder contestants.

if u use ai in abc, it's useless to improve ur coding ability except for a high rating(but its useless

qp

Kind of controversial but about time atcoder banned people from using ai for stuff like language conversion. However its kind of sad that now theres gonna be less brainfck submissions.

I don't think the AI can solve the problems correctly,as they are not as clever as people in some ways.

Yes Just because the AI,make my standing lower

This will be my first contest on the AtCoder.

If I can't solve Problem D,can I give up programming?

Task G is ... GGF's contest's orignal Problem OMGGGGG but i haven't attend.

writers need to do self-check

你改悔吧

Problem $$$D$$$ is constructive cancer.

G is a totally shit. It's the same as this one: https://www.luogu.com.cn/problem/P6240

ABC now becomes a contest that copy other Online Judges' problems, and that is really bad for those who try to solve problems properly.

Also, ABC doesn't ban people who use AI, and that's bad either.

I dont know the error of my solution for D task.

Does anyone knows ?

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<int,char> pic;
#define f first
#define s second

void solve(){
    ll n; cin >> n;
    string str; cin >> str;

    vector<pic> bits;
    ll cont = 1;
    
    for(ll i = 1; i < str.length(); i++){
        char c1 = str[i];
        char c2 = str[i-1];

        if(c1 == c2){
            cont++;
        }else{
            bits.push_back({cont,c2});
            cont  = 1;
        }
    }

    bits.push_back({cont,str[str.length()-1]});
   // for(int i = 0 ;i < bits.size(); i++) cout  << bits[i].f << " " <<bits[i].s << endl;
   // cout << endl;
    pic max_pair = {-1,'c'};
    ll index_max_pair = -1;

    for(ll i = 0; i < bits.size(); i++){
        if(bits[i].f > max_pair.f){
            max_pair = {bits[i].f,bits[i].s};
            index_max_pair = i;
        }
    }

    ll ans = 0;

    for(ll i = 0; i < bits.size(); i++){
        if(i != index_max_pair){
            if(bits[i].second == max_pair.second){
                ans += bits[i].f * 2;
            }else{
                ans += bits[i].f;
            }
        }
    }

    cout << ans << endl;

}

int main(){
    ll t; cin >> t;

    while(t--){
        solve();
    }
}

I love Atluogu.jp !!!

Problem D is great, but EFG are shitty.

E: Totally math problem;

F: Segbeats template;

G: Cattree Divide and Conquer template.

Why there's so many problems that be solved with Segment Tree?!

How to solve E?

Did I need to use calculus in E?

can somebody help me with c

Extremely disgusting E. E can be easily solved by chatGPT in just a few seconds, but human being will get stuck and keep getting wrong answer. This will give cheaters great advantage. They can even have time removing comments and modify the code to make it appear less AI generated looking.

Master like me has already fall below 1600, guess I will eventually reach 1200, and will become Master in codeforces and Pupil in atcoder simultaneously if the problem quality is keep as low as this.

Is G too classic?I think too many people had tried it before the contest began.

I tried ternary search on problem E, but got WA. Is there some corner case for which ternary search would not work?

Please use yuantiji.ac before publishing contests...

"Closest Moment" is another masterpiece after "RLE Moving"

wtf is this??????????

I solved E one minute after the game.Your text to link here...

hp, and this is my first ABC Contest, it is my first discuss in Codeforces too. Good Lucky for me!

S**t F,G.

Shoutout to everyone who solved G by refering the solution of luogu P6240! It really paid off in this contest.

pooper FG

Please do not give geometry problems that involve only simple math anymore.

Hi solved problem D in todays Contest using 2p + dq. Let me know if you guys are interested in a video explanation

#include <bits/stdc++.h>
using namespace std;
namespace __gnu_pbds {}
using namespace __gnu_pbds;
#define fast ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define ll long long
#define ld long double
#define all(v) v.begin(),v.end()
#define F first
#define S second
#define pb push_back
#define mp make_pair
#define pi pair<int,int>
#define pii pair<int,pi>
#define rep(i,n) for(int i=0;i<n;i++)
#define rrep(i,n) for(int i=n-1;i>=0;--i)
#define cusrep(i,a,b,j) for(int i=a;i<b;i+=j)
#define rng(i,a,b) for(int i=a;i<b;i++)
#define rrng(i,a,b) for(int i=a;i>b;--i)
#define ar array

int go(string s, int f, int n, deque<int> dq){
	int l = 0, r = n - 1;
	int op = 0;
	while(l < r){
		if(s[l]!=s[r]){
			if(s[l]!=f) ++l;
			if(s[r]!=f) --r;
			op+=1;
		} else {
			if(s[l]!=f){
				++l;
				--r;
				op+=2;
			} else {
				while(!dq.empty() && dq.front() <= l) dq.pop_front();
				while(!dq.empty() && dq.back() >= r) dq.pop_back();
				if(dq.empty())
					return op;
				int nfi = dq.front();
				int nbi = dq.back();
				if(nfi - l <= r - nbi) ++l;
				else --r;
				op+=2;
			}
		}
	}
	return op;
}
void run_case() {
	int n;
	string s;
	cin >> n >> s;
	deque<int> dq0, dq1;
	rep(i,n){
		if(s[i]=='0')
			dq0.push_back(i);
		else
			dq1.push_back(i);
	}
	int a = go(s, '0', n, dq1);
	int b = go(s, '1', n, dq0);
	cout << min(a,b) << "\n";
}

int main() {
	fast;
	int t;
	cin >> t;
	while(t--){
      run_case();
	}
}

wer contest? why time wrong? I missed it :<

Video Solution of A,B,C,D,E with C++ code of AtCoder Beginner Contest 426: https://youtu.be/Um86KcUtbu0

Before holding this contest,I sunggest problemsetters to use this to check if their problems are new?(I'm sorry for my poor English)

What is the problem with my solution for problem E.

I am Carbon Twelve!

g is p6240 in luogu, so I got the first accepted in g and f is a segbeats template, but remember to use int128.

In the solution to Problem E, "$$$\frac{t}{q}\vec{AB}$$$" should be "$$$\frac{t}{p}\vec{AB}$$$".Because it is $$$\frac{\vec{AB}}{p}$$$ that is the unit vector.