AtCoder Beginner Contest 462 Announcement

atcoder_official's blog

By atcoder_official, history, 3 months ago, In English

We will hold CodeQUEEN 2026 -qual- (AtCoder Beginner Contest 462).

Contest URL: https://atcoder.jp/contests/abc462
Start Time: http://www.timeanddate.com/worldclock/fixedtime.html?iso=20260613T2100&p1=248
Duration: 100 minutes
Writer: sounansya, evima, math957963
Tester: harurun4635, physics0523, sounansya
Rated range: ~ 1999
The point values: 100-200-300-400-450-500-575

We are looking forward to your participation!

-6

atcoder_official
3 months ago
23

Comments (23)

Write comment?

user_7

3 months ago, hide # |

-18

The name is CodeQUEEN. So is it for females only?

→ Reply

MINGZHEXU

3 months ago, hide # ^ |

No.

→ Reply

dengmuyang

3 months ago, hide # ^ |

-13

No.

→ Reply

MINGZHEXU

3 months ago, hide # ^ |

← Rev. 4 →

-13

Dengmuyang and I are both male, but we still registered for CodeQUEEN as usual.

→ Reply

wuchunchen

3 months ago, hide # |

I've made a quick web tool to help everyone check problem scores and estimated difficulties at a glance, which might be useful for your upsolving:
AtCoder Statistics
Any feedback is welcome. Hope it helps with your practice!

→ Reply

alekhsub

3 months ago, hide # ^ |

Noice

→ Reply

ouyangmingze513

3 months ago, hide # |

luck you

→ Reply

dengmuyang

3 months ago, hide # ^ |

Thank you.

→ Reply

Sean222299

3 months ago, hide # |

I want to win

→ Reply

YANGRONGYANG1

3 months ago, hide # |

AtCoder666

→ Reply

Rvess

3 months ago, hide # |

problem G is similar to 1799G. I solved it yesterday lol.

→ Reply

I_Love_Charlie

3 months ago, hide # ^ |

← Rev. 2 →

I found this G to be easier than one in other AtCoder rounds, can be considered north of usual ABC Problem F. Even the points are lower. Anyways, lucky you!!

Surprisingly, problem F was harder to me. I found it better.

→ Reply

Senku

3 months ago, hide # |

F was great

→ Reply

Kayisama

3 months ago, hide # |

-10

I JUST WASTED AN HOUR BEING MISLED BY PROBLEM D!!! I FORGOT THAT TIME SHOULD ALSO BE INCLUDED IN WHAT I'M SOLVING!!!

→ Reply

Terabyte_Connection

3 months ago, hide # |

My first time to solve E.Quite easy.

→ Reply

olosh_chudirvai

3 months ago, hide # |

can anyone tell me what caused WA (C — Not Covered Points)

Code

#include<bits/stdc++.h>
using namespace std;
 
#define int                         long long
#define fastio                      ios::sync_with_stdio(false); cin.tie(nullptr)
 
typedef long long                   ll;    typedef unsigned long long          ull;
typedef double                      db;    typedef long double                 ld;
typedef uint32_t                    u32;   typedef vector<long long>           vll;
typedef vector<int>                 vint;  typedef vector<unsigned long long>  vull;
typedef vector<double>              vdb;   typedef vector<long double>         vld;
typedef vector<vector<int>>         v2d;   typedef vector<pair<int,int>>       vpr;
typedef pair<int,int>               pint;
 
#define vin(_v,_n)                  vint _v(_n); for(auto &_a:_v)cin>>_a;
#define vinr(_a,_v,_l,_r)           for(int _a=_l;_a<=_r;_a++)cin>>_v[_a];
#define vout(_v)                    for(int _a=0;_a<_v.size();_a++)cout<<_v[_a]<<' '; cout<<'\n'
#define voutr(_v,_l,_r)             for(int _a=_l;_a<=_r;_a++)cout<<_v[_a]<<' '; cout<<'\n';
#define fr(_a,aval,_n)              for(int _a=aval;_a<_n;_a++)
#define fre(_a,aval,_n)             for(int _a=aval;_a<=_n;_a++)
#define frv(_a,aval)                for(int _a=aval;_a>=0;_a--)
#define all(_v)                     _v.begin(),_v.end()

int32_t main(){
	// fastio;	
	#ifndef ONLINE_JUDGE		
		freopen("read.in", "r", stdin);
		freopen("read.out", "w", stdout);
	#endif				
	int tc;tc=1;
	// int tc;cin>>tc;		
	for(int ttt=1;ttt<=tc;ttt++){
		#ifndef ONLINE_JUDGE
			cout<<"Testcase : "<<ttt<<'\n';
		#endif
		//---------------------------------------------------------------------------------------//		
		int n;cin>>n;
		vector<pint>vp(n);		
		fr(a,0,n){
			int x,y;cin>>x>>y;
			vp[a]={x,y};			
		}
		int cnt=1;
		int mn=vp[0].second;
		sort(all(vp));		
		fr(a,1,n){
			int x=vp[a].first,y=vp[a].second;
			if(y<mn){
				mn=min(mn,y);
				cnt++;
			}			
		}
		cout<<cnt<<'\n';	
		//---------------------------------------------------------------------------------------//
		#ifndef ONLINE_JUDGE
		//---------------------------------------------------------------------------------------//
		//---------------------------------------------------------------------------------------//
		cout<<'\n';
		#endif
	}
	return 0;
}

→ Reply

_iv

3 months ago, hide # ^ |

← Rev. 2 →

It should be if (y <= mn) instead of if (y < mn), because the boundary is excluded.

(UPD) it's not a problem

→ Reply

I_Love_Charlie

3 months ago, hide # ^ |

← Rev. 3 →

+18

I don't think that is the cause of WA. Assign the value to minY post sorting; or keep it as INF or N + 1 and sweep through all points after sorting.

→ Reply

_iv

3 months ago, hide # ^ |

Yeah, you're right, y is permutation, so comparison type doesn't matter.

→ Reply

olosh_chudirvai

3 months ago, hide # ^ |

Thank u so much for your help. Anyways I made these modifications and then got AC. I wonder how do those modifications make any difference?!

Modifications

#include<bits/stdc++.h>
using namespace std;
 
#define int                         long long
#define fastio                      ios::sync_with_stdio(false); cin.tie(nullptr)
 
typedef long long                   ll;    typedef unsigned long long          ull;
typedef double                      db;    typedef long double                 ld;
typedef uint32_t                    u32;   typedef vector<long long>           vll;
typedef vector<int>                 vint;  typedef vector<unsigned long long>  vull;
typedef vector<double>              vdb;   typedef vector<long double>         vld;
typedef vector<vector<int>>         v2d;   typedef vector<pair<int,int>>       vpr;
typedef pair<int,int>               pint;
 
#define vin(_v,_n)                  vint _v(_n); for(auto &_a:_v)cin>>_a;
#define vinr(_a,_v,_l,_r)           for(int _a=_l;_a<=_r;_a++)cin>>_v[_a];
#define vout(_v)                    for(int _a=0;_a<_v.size();_a++)cout<<_v[_a]<<' '; cout<<'\n'
#define voutr(_v,_l,_r)             for(int _a=_l;_a<=_r;_a++)cout<<_v[_a]<<' '; cout<<'\n';
#define fr(_a,aval,_n)              for(int _a=aval;_a<_n;_a++)
#define fre(_a,aval,_n)             for(int _a=aval;_a<=_n;_a++)
#define frv(_a,aval)                for(int _a=aval;_a>=0;_a--)
#define all(_v)                     _v.begin(),_v.end()

int32_t main(){
	// fastio;	
	#ifndef ONLINE_JUDGE		
		freopen("read.in", "r", stdin);
		freopen("read.out", "w", stdout);
	#endif				
	int tc;tc=1;
	// int tc;cin>>tc;		
	for(int ttt=1;ttt<=tc;ttt++){
		#ifndef ONLINE_JUDGE
			cout<<"Testcase : "<<ttt<<'\n';
		#endif
		//---------------------------------------------------------------------------------------//		
		int n;cin>>n;
		vector<pint>vp(n);		
		fr(a,0,n){
			int x,y;cin>>x>>y;
			vp[a]={x,y};			
		}
		int cnt=0;		// before modification: cnt = 1
		int mn=1e18; 	//before modification: mn = vp[0].second
		sort(all(vp));		
		fr(a,0,n){		//before modification: fr(a,1,n)
			int x=vp[a].first,y=vp[a].second;
			if(y<=mn){ 		//before modification: y<mn
				mn=min(mn,y);
				cnt++;
			}			
		}
		cout<<cnt<<'\n';	
		//---------------------------------------------------------------------------------------//
		#ifndef ONLINE_JUDGE
		//---------------------------------------------------------------------------------------//
		//---------------------------------------------------------------------------------------//
		cout<<'\n';
		#endif
	}
	return 0;
}

→ Reply

_iv

3 months ago, hide # ^ |

The only problem was that you set mn before sorting, so it was just an ordinary y. It should be enough to swap int mn=vp[0].second; and sort(all(vp)); lines in the first code.

→ Reply