Submission #1326103

#	Time	Username	Problem	Language	Result	Execution time	Memory
1326103		vtnoo	Monochrome Points (JOI20_monochrome)	C++20	25 / 100	2095 ms	436 KiB

monochrome

#include <bits/stdc++.h>
#define L(i, j, k) for(int i = (j); i <= (k); i++)
#define R(i, j, k) for(int i = (j); i >= (k); i--)
#define all(x) x.begin(), x.end()
#define sz(a) ((int) a.size())
#define pb push_back
#define fst first
#define snd second
using namespace std;
typedef long long ll;
const int INF=1e9;
int n,m;
int ans=0;
string s;
int calc(vector<pair<int,int>>&p){
	int cur=0;
	L(i,0,n-1){
		for(int j=i+1;j<n;j++){
			int a=p[i].fst,b=p[i].snd;
			int c=p[j].fst,d=p[j].snd;
			bool caso1=(b>c&&a>c&&d>a&&d<b),caso2=(a<d&&a<c&&b>c&&b<d);
			if(caso1||caso2){
				cur++;
			}
		}
	}
	return cur;
}
vector<int>b,w;
int main(){
	ios::sync_with_stdio(false); 
	cin.tie(nullptr);
	cin>>n;
	cin>>s;
	m=n*2;
	L(i,0,m-1){
		if(s[i]=='B')b.pb(i);
		else w.pb(i);
	}
	sort(all(b));
	sort(all(w));
	L(i,0,sz(w)-1){
		vector<pair<int,int>>p;
		int j=0,cur=i;
		int aa=b[j++],bb=w[cur];
		if(aa>bb)swap(aa,bb);
		p.pb({aa,bb});
		L(pasos,1,n-1){
			cur++;
			cur%=n;
			int aa_=b[j++],bb_=w[cur];
			if(aa_>bb_)swap(aa_,bb_);
			p.pb({aa_,bb_});
		}
		//~ cout<<sz(p)<<endl;
		//~ L(i,0,sz(p)-1){
			//~ cout<<p[i].fst+1<<" "<<p[i].snd+1<<endl;
		//~ }
		ans=max(ans,calc(p));
	}
	cout<<ans<<endl;
}

• Subtask 1: 4 / 4
• Subtask 2: 21 / 21
• Subtask 3: 0 / 10
• Subtask 4: 0 / 65