Submission #1015896

#	Time	Username	Problem	Language	Result	Execution time	Memory
1015896		coolsentenceidontremember	Knapsack (NOI18_knapsack)	C++17	100 / 100	75 ms	35328 KiB

knapsack

#include<bits/stdc++.h>

#pragma GCC optimize("O3", "unroll-loops")


#define ll long long
#define ld long double
#define ff first
#define ss second
#define db double
#define time_begin() auto begin = chrono::high_resolution_clock::now()
#define time_end() auto end = chrono::high_resolution_clock::now(); auto elapsed = chrono::duration_cast<chrono::nanoseconds>(end-begin); auto sec = elapsed.count() * 1e-9; cerr << "\n\nExecution time: " << sec << " seconds";
#define check_time() cerr << "\nStatus : "; if (sec>1) cerr << "Time Limit Exceeded 1!!!1!111"; else cerr << "You good brother"

using namespace std;

void setIO(string s = ""){
 ios_base::sync_with_stdio(false);
 cin.tie(nullptr);
 cout.tie(nullptr);
 if (!s.empty()){
	freopen((s+".in").c_str(), "r", stdin);
	freopen((s+".out").c_str(), "w", stdout);
	}
}

// use two dp array to save space

int main(){
	setIO();
	int s, n;
	cin >> s >> n;
	map<int, vector<pair<int, int>>> group;
	for (int i = 1; i <= n; i++){
		int v, w, k;
		cin >> v >> w >> k;
		group[w].push_back({v, k});
	}
	for (auto &[key, val] : group) sort(group[key].begin(), group[key].end(), greater<pair<int, int>>());
	vector<vector<ll>> dp(group.size()+1, vector<ll>(s+1, -LLONG_MAX));
	for (int i = 0; i <= s; i++) dp[0][i] = 0;
	int cur = 0;
	for (auto &[weight, items] : group){
		cur++;
		for (int i = 0; i <= s; i++){
			dp[cur][i] = dp[cur-1][i];
			int num = 0;
			ll val = 0;
			int sz = items.size();
			int cur_item = 0;
			int cnt = 0;
			while (1LL*(num+1)*weight <= i && cur_item < sz && cnt < items[cur_item].ss){
				num++;
				cnt++;
				val += items[cur_item].ff;
				if (dp[cur-1][i-num*weight] != -LLONG_MAX) dp[cur][i] = max(dp[cur][i], dp[cur-1][i-num*weight] + val);
				if (cnt == items[cur_item].ss){
					cnt = 0;
					cur_item++;
				}
			}
		}
		
	}
	cout << *max_element(dp[cur].begin(), dp[cur].end()) << '\n';
}

Compilation message (stderr)

knapsack.cpp: In function 'void setIO(std::string)':
knapsack.cpp:22:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   22 |  freopen((s+".in").c_str(), "r", stdin);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
knapsack.cpp:23:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   23 |  freopen((s+".out").c_str(), "w", stdout);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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