### Introduction↵
↵
Hello, Codeforces!↵
↵
I want to share my suspicions about [user:harsh__h,2025-02-03]. ↵
↵
I wouldn't write the blog if he was not a relatively high ranked individual who both participated in problem setting and testing. Yesterday, I accidentally noted that the 6th place ([standings:2059]), in [contest:2059], which turned to be [user:harsh__h,2025-02-03], had very suspicious submissions. Next, I will try to explain in detail what got my attention in the order in which I uncovered it.↵
↵
### Part 1. Codeforces Round 1002 Div2.↵
↵
During the contest in problems A([submission:304070640]), B([submission:304090034]), C([submission:304111128]) [user:harsh__h,2025-02-03] doesn't use spaces between brackets. That is, he writes, say, `for(ll i=0;i<n;i++){` not `for (ll i = 0; i < n; i++) {`. Also, for the newline he uses endl `cout << mex << endl;`, and these are not interactive problems.↵
↵
Next, In problems D ([submission:304092485]), E([submission:304129652]), in which I think he used chatgpt, harsh__h uses spaces between brackets and keywords, for example, writing `for (ll i = 0; i < n; i++) {` instead of `for(ll i=0;i<n;i++){`. Here for the newline he uses ‘\n', `cout << (ans == inf ? -1 : ans) << '\n';`↵
↵
In addition, compare how he read the graph just a week ago in another graph task [submission:303111414]. A week ago it was↵
↵
~~~~~↵
for(ll i=0;i<n-1;i++){↵
ll x,y;cin>>x>>y;↵
x--;↵
y--;↵
adj[x].push_back(y);↵
adj[y].push_back(x);↵
}↵
~~~~~↵
↵
↵
and yesterday it was ↵
↵
~~~~~↵
for (ll i = 0; i < m1; i++) {↵
ll a, b;↵
cin >> a >> b;↵
--a;↵
--b;↵
g1[a].push_back(b);↵
g1[b].push_back(a);↵
e1.push_back({a, b});↵
}↵
~~~~~↵
↵
Note also, that in [submission:304129652] he doesn’t use spaces even in cin/cout. `cout<<ans<<endl;`↵
↵
To sum up, the submissions look like they were written by different people.↵
↵
After the contest I noted the unusual codestyle and here was his reaction↵
↵
↵
So he didn’t comment on the code style, instead he argued that he solved E1, E2, and that he, Codeforces master, doesn’t know if ChatGPT can solve a very straightforward [problem:2059D].↵
↵
Then, there was this guy [user:MayankBhakat,2025-02-03], probably his friend, who tried very hard to defend [user:harsh__h,2025-02-03], trying to ignore very suspicious codestyle.↵
↵
↵
↵
### Part 2. Educational Codeforces Round 173.↵
↵
First, at this point harsh__h is a master, so [contest:2043] is unrated for him. In this round harsh__h made submissions in very short intervals.↵
↵
Let’s break it down.↵
↵
[problem:2043A]. In this submission [submission:298252659] he doesn’t use his template. Also, it is very unusual when a codeforces master writes 50 lines of code to fail to solve Div2A. Then goes this submission [submission:298254253]. Now it is AC, and apparently, and someone left some comments).↵
↵
Then, just 1 minute after he is done with A, he sends D [submission:298254978], where he also does not use the template.↵
↵
Then, 1 minute after the last D submission, he sends E [submission:298257018] with the same code style as in A, D, which differs significantly from his usual style.↵
↵
Then, 1 minute after the last E submission, he sends F, etc. So the submission history looks like this↵
↵
↵
↵
I think that I made my point.↵
↵
### Part 3. Codeforces Round 956 (Div. 2) and ByteRace 2024 (UPD.1)↵
↵
So, I decided to look into his older submissions. For example, [contest:1983].↵
↵
Consider this submission [submission:269285676] of [problem:1983F]. The codestyle↵
↵
~~~~~↵
while (lo < hi) {↵
ll mid = (lo+hi)/2;↵
if (slv(mid) >= k) hi = mid;↵
else lo = mid+1;↵
}↵
↵
cout << hi << '\n';↵
~~~~~↵
↵
While another problem [problem:1983E] in the very same contest [submission:269275920]↵
↵
~~~~~↵
if(bb%2==0){↵
alice+=(((sum2*(bb))%M)*mod_inv(2,M))%M;↵
}else{↵
alice+=(((sum2*(bb+1))%M)*mod_inv(2,M))%M;↵
}↵
alice%=M;↵
ll bob = sum*aa+sum2*bb-alice;↵
bob%=M;↵
bob+=M;↵
bob%=M;↵
cout<<alice<<" "<<bob<<endl;↵
~~~~~↵
↵
Next, look at problem [problem:1983D], submission [submission:269243749], where he doesn't use `ll` in `count_inversion`↵
↵
~~~~~↵
ll n;cin>>n;↵
vector<int> a(n);↵
cin>>a;↵
vector<int> b(n);↵
cin>>b;↵
auto count_inversion=[&](vector<int> arr)->long long{↵
↵
int n = (int)arr.size();↵
↵
vector<int> buffer(n);↵
↵
function<long long(int,int,int,int)> combine=[&](int left_l,int left_r,int right_l,int right_r)->long long{↵
int r_pointer=left_r;↵
long long cnt=0;↵
...↵
~~~~~↵
↵
In addition, check the comments for additional suspicios cases. So [user:harsh__h,2025-02-03] has a quite long history of making very suspicious submissions. His results in these contests should be investigated, in my opinion.↵
↵
### Conclusion↵
↵
Could you please [user:MikeMirzayanov,2025-02-03], [user:Vladosiya,2025-02-03], [user:KAN,2025-02-03] check the submissions? [user:harsh__h,2025-02-03] participated in problem setting and in testing in the past. I believe that this case should be investigated to keep the integrity and fairness of the future rounds. I really hope that [user:harsh__h,2025-02-03] just has a very peculiar codestyle. Unfortunately, I am not sure at all that this is the case.↵
↵
Also, I tried my best to not make any accusations but unfortunately the reaction of [user:harsh__h,2025-02-03] [user:MayankBhakat,2025-02-03] made me too emotional in my comments. For that I am deeply sorry.
↵
Hello, Codeforces!↵
↵
I want to share my suspicions about [user:harsh__h,2025-02-03]. ↵
↵
I wouldn't write the blog if he was not a relatively high ranked individual who both participated in problem setting and testing. Yesterday, I accidentally noted that the 6th place ([standings:2059]), in [contest:2059], which turned to be [user:harsh__h,2025-02-03], had very suspicious submissions. Next, I will try to explain in detail what got my attention in the order in which I uncovered it.↵
↵
### Part 1. Codeforces Round 1002 Div2.↵
↵
During the contest in problems A([submission:304070640]), B([submission:304090034]), C([submission:304111128]) [user:harsh__h,2025-02-03] doesn't use spaces between brackets. That is, he writes, say, `for(ll i=0;i<n;i++){` not `for (ll i = 0; i < n; i++) {`. Also, for the newline he uses endl `cout << mex << endl;`, and these are not interactive problems.↵
↵
Next, In problems D ([submission:304092485]), E([submission:304129652]), in which I think he used chatgpt, harsh__h uses spaces between brackets and keywords, for example, writing `for (ll i = 0; i < n; i++) {` instead of `for(ll i=0;i<n;i++){`. Here for the newline he uses ‘\n', `cout << (ans == inf ? -1 : ans) << '\n';`↵
↵
In addition, compare how he read the graph just a week ago in another graph task [submission:303111414]. A week ago it was↵
↵
~~~~~↵
for(ll i=0;i<n-1;i++){↵
ll x,y;cin>>x>>y;↵
x--;↵
y--;↵
adj[x].push_back(y);↵
adj[y].push_back(x);↵
}↵
~~~~~↵
↵
↵
and yesterday it was ↵
↵
~~~~~↵
for (ll i = 0; i < m1; i++) {↵
ll a, b;↵
cin >> a >> b;↵
--a;↵
--b;↵
g1[a].push_back(b);↵
g1[b].push_back(a);↵
e1.push_back({a, b});↵
}↵
~~~~~↵
↵
Note also, that in [submission:304129652] he doesn’t use spaces even in cin/cout. `cout<<ans<<endl;`↵
↵
To sum up, the submissions look like they were written by different people.↵
↵
After the contest I noted the unusual codestyle and here was his reaction↵
↵
↵
So he didn’t comment on the code style, instead he argued that he solved E1, E2, and that he, Codeforces master, doesn’t know if ChatGPT can solve a very straightforward [problem:2059D].↵
↵
Then, there was this guy [user:MayankBhakat,2025-02-03], probably his friend, who tried very hard to defend [user:harsh__h,2025-02-03], trying to ignore very suspicious codestyle.↵
↵
↵
↵
### Part 2. Educational Codeforces Round 173.↵
↵
First, at this point harsh__h is a master, so [contest:2043] is unrated for him. In this round harsh__h made submissions in very short intervals.↵
↵
Let’s break it down.↵
↵
[problem:2043A]. In this submission [submission:298252659] he doesn’t use his template. Also, it is very unusual when a codeforces master writes 50 lines of code to fail to solve Div2A. Then goes this submission [submission:298254253]. Now it is AC, and apparently, and someone left some comments).↵
↵
Then, just 1 minute after he is done with A, he sends D [submission:298254978], where he also does not use the template.↵
↵
Then, 1 minute after the last D submission, he sends E [submission:298257018] with the same code style as in A, D, which differs significantly from his usual style.↵
↵
Then, 1 minute after the last E submission, he sends F, etc. So the submission history looks like this↵
↵
↵
↵
I think that I made my point.↵
↵
### Part 3. Codeforces Round 956 (Div. 2) and ByteRace 2024 (UPD.1)↵
↵
So, I decided to look into his older submissions. For example, [contest:1983].↵
↵
Consider this submission [submission:269285676] of [problem:1983F]. The codestyle↵
↵
~~~~~↵
while (lo < hi) {↵
ll mid = (lo+hi)/2;↵
if (slv(mid) >= k) hi = mid;↵
else lo = mid+1;↵
}↵
↵
cout << hi << '\n';↵
~~~~~↵
↵
While another problem [problem:1983E] in the very same contest [submission:269275920]↵
↵
~~~~~↵
if(bb%2==0){↵
alice+=(((sum2*(bb))%M)*mod_inv(2,M))%M;↵
}else{↵
alice+=(((sum2*(bb+1))%M)*mod_inv(2,M))%M;↵
}↵
alice%=M;↵
ll bob = sum*aa+sum2*bb-alice;↵
bob%=M;↵
bob+=M;↵
bob%=M;↵
cout<<alice<<" "<<bob<<endl;↵
~~~~~↵
↵
Next, look at problem [problem:1983D], submission [submission:269243749], where he doesn't use `ll` in `count_inversion`↵
↵
~~~~~↵
ll n;cin>>n;↵
vector<int> a(n);↵
cin>>a;↵
vector<int> b(n);↵
cin>>b;↵
auto count_inversion=[&](vector<int> arr)->long long{↵
↵
int n = (int)arr.size();↵
↵
vector<int> buffer(n);↵
↵
function<long long(int,int,int,int)> combine=[&](int left_l,int left_r,int right_l,int right_r)->long long{↵
int r_pointer=left_r;↵
long long cnt=0;↵
...↵
~~~~~↵
↵
In addition, check the comments for additional suspicios cases. So [user:harsh__h,2025-02-03] has a quite long history of making very suspicious submissions. His results in these contests should be investigated, in my opinion.↵
↵
### Conclusion↵
↵
Could you please [user:MikeMirzayanov,2025-02-03], [user:Vladosiya,2025-02-03], [user:KAN,2025-02-03] check the submissions? [user:harsh__h,2025-02-03] participated in problem setting and in testing in the past. I believe that this case should be investigated to keep the integrity and fairness of the future rounds. I really hope that [user:harsh__h,2025-02-03] just has a very peculiar codestyle. Unfortunately, I am not sure at all that this is the case.↵
↵
Also, I tried my best to not make any accusations but unfortunately the reaction of [user:harsh__h,2025-02-03] [user:MayankBhakat,2025-02-03] made me too emotional in my comments. For that I am deeply sorry.
