Submission #954855

#	Time	Username	Problem	Language	Result	Execution time	Memory
954855		mat_jur	Feast (NOI19_feast)	C++17	100 / 100	220 ms	16068 KiB

feast

#include <bits/stdc++.h>
using namespace std;
#ifdef DEBUG
auto&operator<<(auto &o, pair<auto, auto> p) {o << "(" << p.first << ", " << p.second << ")"; return o;}
auto operator<<(auto &o, auto x)->decltype(x.end(), o) {o<<"{"; for(auto e : x) o<<e<<", "; return o<<"}";}
#define debug(X) cerr << "["#X"]: " << X << '\n';
#else 
#define cerr if(0)cout
#define debug(X) ;
#endif
using ll = long long;
#define all(v) (v).begin(), (v).end()
#define ssize(x) int(x.size())
#define fi first
#define se second
#define mp make_pair
#define eb emplace_back

int main() {
	ios_base::sync_with_stdio(false); cin.tie(nullptr);

	int n, k;
	cin >> n >> k;
	vector<int> a(n);
	for(int &x : a) cin >> x;

	auto solve_lambda = [&](ll lambda) {
		vector<pair<ll, int>> dp[2];
		dp[0].resize(n);
		dp[1].resize(n);

		dp[0][0] = mp(0LL, 0);
		dp[1][0] = mp(a[0] - lambda, 1);
		for(int i = 1; i < n; ++i) {
			dp[0][i] = max(dp[0][i-1], dp[1][i-1]);
			dp[1][i] = max(mp(dp[1][i-1].fi + a[i], dp[1][i-1].se), mp(dp[0][i-1].fi + a[i] - lambda, dp[0][i-1].se + 1));
		}
		return max(dp[0][n-1], dp[1][n-1]);
	};

	ll low = 0, high = 1e15;
	while (high - low > 1) {
		ll mid = (high + low) / 2;
		if(solve_lambda(mid).se >= k) low = mid;
		else high = mid;
	}

	debug(low);
	auto [u, c] = solve_lambda(low);
	debug(u);
	debug(c);
	cout << u + k * low << '\n';

	return 0;
}

• Subtask 1: 4 / 4
• Subtask 2: 8 / 8
• Subtask 3: 18 / 18
• Subtask 4: 10 / 10
• Subtask 5: 11 / 11
• Subtask 6: 20 / 20
• Subtask 7: 29 / 29