Submission #767705

#	Time	Username	Problem	Language	Result	Execution time	Memory
767705		marvinthang	Meetings (IOI18_meetings)	C++17	60 / 100	381 ms	196472 KiB

meetings

/*************************************
*    author: marvinthang             *
*    created: 27.06.2023 11:42:33    *
*************************************/

#include "meetings.h"
#include <bits/stdc++.h>

using namespace std;

#define                  fi  first
#define                  se  second
#define                left  ___left
#define               right  ___right
#define                TIME  (1.0 * clock() / CLOCKS_PER_SEC)
#define             MASK(i)  (1LL << (i))
#define           BIT(x, i)  ((x) >> (i) & 1)
#define  __builtin_popcount  __builtin_popcountll
#define              ALL(v)  (v).begin(), (v).end()
#define           REP(i, n)  for (int i = 0, _n = (n); i < _n; ++i)
#define          REPD(i, n)  for (int i = (n); i--; )
#define        FOR(i, a, b)  for (int i = (a), _b = (b); i < _b; ++i) 
#define       FORD(i, b, a)  for (int i = (b), _a = (a); --i >= _a; ) 
#define       FORE(i, a, b)  for (int i = (a), _b = (b); i <= _b; ++i) 
#define      FORDE(i, b, a)  for (int i = (b), _a = (a); i >= _a; --i) 
#define        scan_op(...)  istream & operator >> (istream &in, __VA_ARGS__ &u)
#define       print_op(...)  ostream & operator << (ostream &out, const __VA_ARGS__ &u)
#ifdef LOCAL
    #include "debug.h"
#else
    #define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
    #define DB(...) 23
    #define db(...) 23
    #define debug(...) 23
#endif

template <class U, class V> scan_op(pair <U, V>)  { return in >> u.first >> u.second; }
template <class T> scan_op(vector <T>)  { for (size_t i = 0; i < u.size(); ++i) in >> u[i]; return in; }
template <class U, class V> print_op(pair <U, V>)  { return out << '(' << u.first << ", " << u.second << ')'; }
template <size_t i, class T> ostream & print_tuple_utils(ostream &out, const T &tup) { if constexpr(i == tuple_size<T>::value) return out << ")";  else return print_tuple_utils<i + 1, T>(out << (i ? ", " : "(") << get<i>(tup), tup); }
template <class ...U> print_op(tuple<U...>) { return print_tuple_utils<0, tuple<U...>>(out, u); }
template <class Con, class = decltype(begin(declval<Con>()))> typename enable_if <!is_same<Con, string>::value, ostream&>::type operator << (ostream &out, const Con &con) { out << '{'; for (__typeof(con.begin()) it = con.begin(); it != con.end(); ++it) out << (it == con.begin() ? "" : ", ") << *it; return out << '}'; }
template <class A, class B> bool minimize(A &a, B b)  { if (a > b) { a = b; return true; } return false; }
template <class A, class B> bool maximize(A &a, B b)  { if (a < b) { a = b; return true; } return false; }

// end of template

const long long INF = 1e18;

vector <long long> minimum_costs(std::vector<int> H, vector <int> L, vector <int> R) {
	int N = H.size();
	int Q = L.size();
	vector <long long> ans;
	if (max(N, Q) <= 5000) {
		vector <vector <long long>> cost;
		REP(i, N) {
			vector <long long> pref(N + 1);
			pref[i + 1] = H[i];
			REPD(j, i) pref[j + 1] = max(1LL * H[j], pref[j + 2]);
			FOR(j, i + 1, N) pref[j + 1] = max(1LL * H[j], pref[j]);
			partial_sum(ALL(pref), pref.begin());
			cost.push_back(pref);
		}
		REP(i, Q) {
			long long res = INF;
			FORE(j, L[i], R[i]) minimize(res, cost[j][R[i] + 1] - cost[j][L[i]]);
			ans.push_back(res);
		}
		return ans;
	}
	int k = *max_element(ALL(H));
	if (k > 20) return ans;

	stack <int> st;
	vector <vector <int>> nxt(N, vector<int>(k + 1, N)), prv(N, vector<int>(k + 1, 0));
	vector <long long> cost_left(N), cost_right(N);
	vector <int> left(N), right(N);
	REP(i, N) {
		while (!st.empty() && H[st.top()] <= H[i]) st.pop();
		if (st.empty()) {
			left[i] = -1;
			cost_left[i] = 1LL * H[i] * (i + 1);
		}
		else {
			left[i] = st.top();
			cost_left[i] = 1LL * H[i] * (i - left[i]) + cost_left[left[i]];
		}
		st.push(i);
		if (i) prv[i] = prv[i - 1];
		prv[i][H[i]] = i;
	}
	while (!st.empty()) st.pop();
	REPD(i, N) {
		while (!st.empty() && H[st.top()] <= H[i]) st.pop();
		if (st.empty()) {
			right[i] = N;
			cost_right[i] = 1LL * H[i] * (N - i);
		} else {
			right[i] = st.top();
			cost_right[i] = 1LL * H[i] * (right[i] - i) + cost_right[right[i]];
		}
		st.push(i);
		if (i + 1 < N) nxt[i] = nxt[i + 1];
		nxt[i][H[i]] = i;
	}

	vector <vector <long long>> mi_st;
	mi_st.push_back(vector<long long>(N));
	REP(i, N) mi_st[0][i] = cost_left[i] + cost_right[i] - H[i];
	for (int k = 1; MASK(k) <= N; ++k) {
		vector <long long> nxt;
		REP(i, N - MASK(k) + 1) nxt.push_back(min(mi_st.back()[i], mi_st.back()[i + MASK(k - 1)]));
		mi_st.push_back(nxt);
	}
	auto get_min = [&] (int l, int r) {
		int h = __lg(r - l + 1);
		return min(mi_st[h][l], mi_st[h][r - MASK(h) + 1]);
	};

	REP(q, Q) {
		int ma = k;
		while (nxt[L[q]][ma] > R[q]) --ma;
		long long res = INF;
		FORE(km, 1, ma) {
			int l = nxt[L[q]][km];
			int r = prv[R[q]][ma];
			if (left[l] < L[q] && l <= r) {
				long long cur = get_min(l, r);
				cur -= km * (L[q] - left[l] - 1) + (~left[l] ? cost_left[left[l]] : 0);
				cur -= ma * (right[r] - R[q] - 1) + (right[r] < N ? cost_right[right[r]] : 0);
				minimize(res, cur);
			}
			l = nxt[L[q]][ma];
			r = prv[R[q]][km];
			if (right[r] > R[q] && l <= r) {
				long long cur = get_min(l, r);
				cur -= ma * (L[q] - left[l] - 1) + (~left[l] ? cost_left[left[l]] : 0);
				cur -= km * (right[r] - R[q] - 1) + (right[r] < N ? cost_right[right[r]] : 0);
				minimize(res, cur);
			}
		}
		ans.push_back(res);
	}
	return ans;
}

#ifdef LOCAL
#include <cstdio>
#include <cstdlib>
#include <vector>
#include "meetings.h"

namespace {

int read_int() {
	int x;
	if (scanf("%d", &x) != 1) {
		fprintf(stderr, "Error while reading input\n");
		exit(1);
	}
	return x;
}

}  // namespace

int main() {
	file("meetings");
	int N = read_int();
	int Q = read_int();
	std::vector<int> H(N);
	for (int i = 0; i < N; ++i) {
		H[i] = read_int();
	}
	std::vector<int> L(Q), R(Q);
	for (int j = 0; j < Q; ++j) {
		L[j] = read_int();
		R[j] = read_int();
	}

	std::vector<long long> C = minimum_costs(H, L, R);
	for (size_t j = 0; j < C.size(); ++j) {
		printf("%lld\n", C[j]);
	}
	return 0;
}
#endif

• Subtask 1: 4 / 4
• Subtask 2: 15 / 15
• Subtask 3: 17 / 17
• Subtask 4: 24 / 24
• Subtask 5: 0 / 40