oj.uz

Submission #427970

# Submission time Handle Problem Language Result Execution time Memory
427970 2021-06-15T06:21:35 Z cfalas Monochrome Points (JOI20_monochrome) C++14
0 / 100
 1 ms 204 KB 
#include<bits/stdc++.h>
using namespace std;
#define mp make_pair
#define INF 10000000
#define MOD 1000000007
#define MID ((l+r)/2)
#define HASHMOD 2305843009213693951
#define ll long long
#define ull unsigned long long
#define F first
#define S second
typedef pair<ll, ll> ii;
typedef pair<ii, int> iii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef map<int, int> mii;

#define EPS 1e-6
#define FOR(i,n) for(int i=0;i<((int)(n));i++)
#define FORi(i,a,b) for(int i=((int)(a));i<((int)(b));i++)
#define FOA(v, a) for(auto v : a)

int t, n;

int dist(int a, int b){
	return min(abs(a-b), abs(a-b+n));
}

int bp[400000];
int wp[400000];
int br(int l, int r){
	if(l>r) return 0;
	if(l==0) return bp[r];
	else return bp[r] - bp[l-1];
}
int wr(int l, int r){
	if(l>r) return 0;
	if(l==0) return wp[r];
	else return wp[r] - wp[l-1];
}
set<int> w, b;

ll gans(int off){
	auto it = b.begin();
	FOR(i,off) it++;
	ll ans=0;
	FOA(v,w){
		//cout<<v<<" "<<*it<<endl;
		int mi = min(v, *it);
		int ma = max(v, *it);
		ans += min(br(mi+1,ma-1) , (wr(0,mi-1) + wr(ma+1,n-1))) + min(br(0,mi-1) + br(ma+1,n-1) , (wr(mi+1,ma-1)));
		//cout<<v<<" "<<*it<<" "<<ans<<endl;

		it++;
		if(it==b.end()) it = b.begin();
	}
	return ans;
}

int main(){
	cin>>n;
	string s;
	cin>>s;
	n*=2;
	bp[0] = (s[0]=='B');
	FORi(i,1,n){
		bp[i] = bp[i-1];
		if(s[i]=='B') bp[i]++;
	}
	wp[0] = (s[0]=='W');
	FORi(i,1,n){
		wp[i] = wp[i-1];
		if(s[i]=='W') wp[i]++;
	}
	FOR(i,n){
		if(s[i]=='W') w.insert(i);
		else b.insert(i);
	}

	ll bans=0;
	int l=0, r=n/2+1;
	int m = MID;
	while(l<r-1){
		ll a1 = gans((l+m)/2);
		bans = max(bans, a1);
		ll a2 = gans((r+m)/2);
		bans = max(bans, a2);
		if(a1<=a2){
			l = m;
			m = MID;
		}
		else{
			r = m;
			m = MID;
		}
		//cout<<ans<<endl;
	}
	cout<<bans/2<<endl;
}

Subtask #1
0.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 204 KB Output is correct
2 Correct 1 ms 204 KB Output is correct
3 Correct 1 ms 204 KB Output is correct
4 Correct 1 ms 204 KB Output is correct
5 Correct 1 ms 204 KB Output is correct
6 Correct 1 ms 204 KB Output is correct
7 Incorrect 1 ms 204 KB Output isn't correct
8 Halted 0 ms 0 KB -

Subtask #2
0.0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 204 KB Output is correct
2 Correct 1 ms 204 KB Output is correct
3 Correct 1 ms 204 KB Output is correct
4 Correct 1 ms 204 KB Output is correct
5 Correct 1 ms 204 KB Output is correct
6 Correct 1 ms 204 KB Output is correct
7 Incorrect 1 ms 204 KB Output isn't correct
8 Halted 0 ms 0 KB -

Subtask #3
0.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 204 KB Output is correct
2 Correct 1 ms 204 KB Output is correct
3 Correct 1 ms 204 KB Output is correct
4 Correct 1 ms 204 KB Output is correct
5 Correct 1 ms 204 KB Output is correct
6 Correct 1 ms 204 KB Output is correct
7 Incorrect 1 ms 204 KB Output isn't correct
8 Halted 0 ms 0 KB -

Subtask #4
0.0 / 65.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 204 KB Output is correct
2 Correct 1 ms 204 KB Output is correct
3 Correct 1 ms 204 KB Output is correct
4 Correct 1 ms 204 KB Output is correct
5 Correct 1 ms 204 KB Output is correct
6 Correct 1 ms 204 KB Output is correct
7 Incorrect 1 ms 204 KB Output isn't correct
8 Halted 0 ms 0 KB -