Submission #918776

#	Time	Username	Problem	Language	Result	Execution time	Memory
918776		waldi	Monochrome Points (JOI20_monochrome)	C++17	35 / 100	2029 ms	10440 KiB

monochrome

#include <bits/stdc++.h>
#define FOR(i,p,k) for(int i=(p);i<=(k);++i)
#define REP(i,n) FOR(i,0,(n)-1)
#define ssize(x) (int(x.size()))
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
using namespace std;
typedef pair<int, int> pii;

struct przedzialowiec{
	int N;
	vector<int> t;
	przedzialowiec(int n){
		for(N = 1; N <= n;) N <<= 1;
		t.resize(N<<1, 0);
	}
	void dodaj(int poz){
		for(poz+=N; poz; poz>>=1) ++t[poz];
	}
	int suma(int p, int k){
		int ret = 0;
		for(p+=N, k+=N+1; p<k; p>>=1, k>>=1){
			if(p&1) ret += t[p++];
			if(k&1) ret += t[--k];
		}
		return ret;
	}
};

int main(){
	int n;
	scanf("%d\n", &n);
	int n2 = n<<1;
	vector<int> s(n2);
	REP(i, n2){
		char c;
		scanf("%c", &c);
		s[i] = c=='B';
	}
	
	int wyn = 0;
	REP(xd, n){
		vector<pii> prz;
		
		vector<vector<int>> lewo(2), prawo(2);
		REP(i, n) lewo[s[i]].emplace_back(i);
		FOR(i, n, n2-1) prawo[s[i]].emplace_back(i);
		REP(i, ssize(lewo[0])) prz.emplace_back(lewo[0][i], prawo[1][i]);
		REP(i, ssize(lewo[1])) prz.emplace_back(lewo[1][i], prawo[0][i]);
		
		int tmp = 0;
		sort(all(prz));
		przedzialowiec przed(n);
		REP(i, n){
			pii t = prz[i];
			tmp += przed.suma(0, t.se-n);
			przed.dodaj(t.se-n);
		}
		wyn = max(wyn, tmp);
		
		s.insert(s.begin(), s.back());
		s.pop_back();
	}
	printf("%d", wyn);
	return 0;
}

Compilation message (stderr)

monochrome.cpp: In function 'int main()':
monochrome.cpp:33:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   33 |  scanf("%d\n", &n);
      |  ~~~~~^~~~~~~~~~~~
monochrome.cpp:38:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   38 |   scanf("%c", &c);
      |   ~~~~~^~~~~~~~~~

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