Submission #537864

#	Time	Username	Problem	Language	Result	Execution time	Memory
537864		michao	Monochrome Points (JOI20_monochrome)	C++14	35 / 100	2088 ms	4328 KiB

monochrome

#include <bits/stdc++.h>
#define int long long
#define mp make_pair
#define pb push_back
#define ld long double
#define pii pair<int,int>
#define sz(x) (int)x.size()
#define piii pair<pii,pii>
#define precise cout<<fixed<<setprecision(10)
#define st first
#define nd second
#define ins insert
#define vi vector<int>
#define BOOST ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0)
using namespace std;
const int MAX=2e5+5;
vi b,w;
char s[MAX*2];
int ans=0;
int n;

int ile(int x,int y){
	if (x>y)swap(x,y);
	int between=y-x-1;
	return min(n*2-2-between,between);
}

int f(int shift){
	int sum=0;
	assert(sz(b)==sz(w) && sz(b)==n);
	for (int i=0;i<n;i++){
		int x=b[i];
		int y=w[(i+shift)%n];
		//if (shift==1)cout<<"TERAZ "<<x<<" "<<y<<" "<<ile(x,y)<<"\n";
		sum+=ile(x,y);
	}
	return sum/2;
}
int32_t main(){
  BOOST;
  cin>>n;
  for (int i=0;i<n*2;i++){
		cin>>s[i];
		if (s[i]=='B')b.pb(i);
		else w.pb(i);
  }
  
  for (int i=0;i<=n-1;i++){
		ans=max(ans,f(i));
  }
  cout<<ans;
  return 0; 
}

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