Submission #529307

#	Time	Username	Problem	Language	Result	Execution time	Memory
529307		Bungmint	Knapsack (NOI18_knapsack)	C++17	12 / 100	1 ms	324 KiB

knapsack

//Copyright © 2021 Youngmin Park. All rights reserved.
#pragma GCC optimize("O3")
#pragma GCC target("avx2")
#include <bits/stdc++.h>
using namespace std;

using ll = long long;
using vi = vector<int>;
using pii = pair<int, int>;
using vpi = vector<pii>;
using pll = pair<ll, ll>;
using vl = vector<ll>;
using vpl = vector<pll>;
using ld = long double;
template <typename T, size_t SZ>
using ar = array<T, SZ>;

#define all(v) (v).begin(), (v).end()
#define pb push_back
#define sz(x) (int)(x).size()
#define fi first
#define se second
#define lb lower_bound
#define ub upper_bound
#define FOR(i, a, b) for (int i = (a); i < (b); ++i)
#define F0R(i, a) FOR(i, 0, a)
#define ROF(i, a, b) for (int i = (b)-1; i >= (a); --i)
#define R0F(i, a) ROF(i, 0, a)
#define REP(a) F0R(_, a)

const int INF = 1e9;
const ll LINF = 1e18;
const int MOD = 1e9 + 7; //998244353;
const ld PI = acos((ld)-1.0);
const int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
template <typename T>
using pqg = priority_queue<T, vector<T>, greater<T>>;
template <typename T>
bool ckmin(T &a, const T &b) { return b < a ? a = b, 1 : 0; }
template <typename T>
bool ckmax(T &a, const T &b) { return b > a ? a = b, 1 : 0; }

template <typename A, typename B>
ostream &operator<<(ostream &os, const pair<A, B> &p)
{
    return os << '(' << p.first << ", " << p.second << ')';
}
template <typename T_container, typename T = typename enable_if<!is_same<T_container, string>::value, typename T_container::value_type>::type>
ostream &operator<<(ostream &os, const T_container &v)
{
    os << '{';
    string sep;
    for (const T &x : v)
        os << sep << x, sep = ", ";
    return os << '}';
}
void dbg_out()
{
    cerr << endl;
}
template <typename Head, typename... Tail>
void dbg_out(Head H, Tail... T)
{
    cerr << ' ' << H;
    dbg_out(T...);
}
#ifdef LOCAL
#define dbg(...) cerr << "(" << #__VA_ARGS__ << "):", dbg_out(__VA_ARGS__)
#else
#define dbg(...) 42
#endif

inline namespace RecursiveLambda{
	template <typename Fun>
	struct y_combinator_result{
		Fun fun_;
		template <typename T> 
		explicit y_combinator_result(T &&fun): fun_(forward<T>(fun)){}
		template <typename...Args>
		decltype(auto) operator()(Args &&...args){
			return fun_(ref(*this), forward<Args>(args)...);
		}
	};
	template <typename Fun>
	decltype(auto) y_combinator(Fun &&fun){
		return y_combinator_result<decay_t<Fun>>(forward<Fun>(fun));
	}
};

void setIO(string s) // USACO
{
	#ifndef LOCAL
	    freopen((s + ".in").c_str(), "r", stdin);
	    freopen((s + ".out").c_str(), "w", stdout);
	#endif
}

const int S = 2000;
ll dp[2][S + 1];


void solve()
{
	int n, s;
	cin >> s >> n;
	int previous = 1, current = 0;
	// memset(dp, -1, 2 * (S + 1) * sizeof(ll));
	// dp[previous][0] = 0;
	REP(n) {
		int v, w, k;
		cin >> v >> w >> k;
		FOR(i, 0, w) {
			stack<ll> L, R, maxL, maxR;
			ll C = 0;
			auto remove = [&]() -> void {
				if (!sz(L)) {
					while (sz(R)) {
						L.push(R.top());
						maxL.push(max((maxL.empty() ? -LINF : maxL.top()), L.top()));
						R.pop();
						maxR.pop();
					}
				}
				L.pop();
				maxL.pop();
			};
			auto add = [&](ll val) -> void {
				R.push(val);
				maxR.push(max((maxR.empty() ? -LINF : maxR.top()), val));
			};
			auto get = [&]() -> ll {
				ll val = -LINF;
				if (sz(maxL)) ckmax(val, maxL.top());
				if (sz(maxR)) ckmax(val, maxR.top());
				return val;
			};
			for (int j = i; j <= s; j += w) {
				while (sz(L) + sz(R) > k) {
					remove();
				}
				C += v;
				if (ll val = get(); val != -LINF){
					ckmax(dp[current][j], val + C);	
				}
				add(dp[previous][j] - C);
			}
		}
		swap(previous, current);
	}
	cout << *max_element(dp[previous], dp[previous] + s + 1) << "\n";
}

int main()
{
    cin.tie(0)->sync_with_stdio(0);
    cin.exceptions(cin.failbit);
    int testcase=1;
    // cin >> testcase;
    while (testcase--)
    {
        solve();
    }
}

Compilation message (stderr)

knapsack.cpp: In function 'void setIO(std::string)':
knapsack.cpp:94:13: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   94 |      freopen((s + ".in").c_str(), "r", stdin);
      |      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
knapsack.cpp:95:13: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   95 |      freopen((s + ".out").c_str(), "w", stdout);
      |      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 12 / 12
• Subtask 2: 0 / 17
• Subtask 3: 0 / 20
• Subtask 4: 0 / 24
• Subtask 5: 0 / 27