Submission #848186

#	Time	Username	Problem	Language	Result	Execution time	Memory
848186		KN200711	Election (BOI18_election)	C++14	0 / 100	9 ms	27736 KiB

election

# include <bits/stdc++.h>
# define fi first
# define se second
using namespace std;

vector< pair<int, int> > pref[500001], suff[500001];
int ans[500001];
int N;
string S;

const int MXN = 5e5 + 1;
int fen[MXN + 1];

void upd(int a, int b) {
	while(a <= MXN) {
		fen[a] += b;
		a += a&(-a);
	}
}

int qry(int a) {
	int fn = 0;
	while(a > 0) {
		fn += fen[a];
		a -= a&(-a);
	}
	return fn;
}

void calc() {
	vector< pair<int, int> > L, V;
	L.clear();
	V.clear();
	for(int i=0;i<=MXN;i++) fen[i] = 0;
	
	for(int i=0;i<N;i++) {
	//	cout<<i<<endl;
		if(V.size() == 0) V.push_back(make_pair(i, i));
		else {
			while(V.back().se != i - 1) {
				
			}
			V.back().se++;
		}
		
		if(S[i] == 'C') {
			if(V.size() == 0) {
				L.back().se++;
			} else {
				L.push_back(V.back());
				L.push_back(make_pair(-1, 1));
				V.clear();
			}
		} else {
			if(V.size() == 1) {
				upd(V.back().fi + 1, 1);
				upd(V.back().se + 2, -1);
			}
		//	if(V.size() > 0) cout<<i<<" "<<V.back().fi<<" "<<V.back().se<<endl;
			if(L.size() && L.back().se == 1) {
				L.pop_back();
				if(V.size() == 0) V.push_back(L.back());
				else V.back().fi = L.back().fi;
				
				L.pop_back();
			} else if(L.size()) L.back().se--;
		}
		
		
		for(int k=0;k<pref[i].size();k++) {
		//	cout<<"qry : "<<pref[i][k].se<<" "<<pref[i][k].fi<<endl;
			ans[pref[i][k].se] = max(ans[pref[i][k].se], qry(pref[i][k].fi + 1));
		}
	}
}

int main() {
	cin>>N;
	cin>>S;
	
	int Q;
	cin>>Q;
	for(int tc = 1;tc<=Q;tc++) {
		int a, b;
		cin>>a>>b;
		if(a > b) swap(a, b);
		a--;
		b--;
		pref[b].push_back(make_pair(a, tc));
		suff[a].push_back(make_pair(b, tc));
	}
	
	
	// calculate prefnya dulu
	calc();
	
	string T = "";
	for(int i=N-1;i>=0;i--) T += S[i];
	S = T;
	for(int i=0;i<N;i++) pref[i].clear();
	for(int i=N-1;i>=0;i--) {
		for(int k=0;k<suff[i].size();k++) {
			pref[N - i - 1].push_back(make_pair(N - suff[i][k].fi - 1, suff[i][k].se));
		}
	}
	
	calc();
	for(int i=1;i<=Q;i++) cout<<ans[i]<<"\n";
	return 0;
}

Compilation message (stderr)

election.cpp: In function 'void calc()':
election.cpp:70:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   70 |   for(int k=0;k<pref[i].size();k++) {
      |               ~^~~~~~~~~~~~~~~
election.cpp: In function 'int main()':
election.cpp:102:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  102 |   for(int k=0;k<suff[i].size();k++) {
      |               ~^~~~~~~~~~~~~~~

• Subtask 1: 0 / 28
• Subtask 2: 0 / 54
• Subtask 3: 0 / 18