Submission #1203643

#	Time	Username	Problem	Language	Result	Execution time	Memory
1203643		timeflew	Knapsack (NOI18_knapsack)	C++20	73 / 100	1095 ms	560 KiB

knapsack

//gpt4
#include <bits/stdc++.h>
using namespace std;
using ll = long long;

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

    int S, N;
    cin >> S >> N;

    vector<ll> dp(S+1, 0);

    for(int i = 0; i < N; i++){
        ll V, W, K;
        cin >> V >> W >> K;

        // 1) If effectively infinite, do complete‐knapsack
        if (K * W >= S) {
            for(int j = W; j <= S; ++j){
                dp[j] = max(dp[j], dp[j - W] + V);
            }
        }
        // 2) Otherwise do bounded‐knapsack via sliding‐window
        else {
            // process each residue class modulo W
            for(int r = 0; r < W; r++){
                deque<pair<ll,int>> dq;
                // iterate k = 0,1,2,... with position pos = r + k*W
                for(int k = 0, pos = r; pos <= S; ++k, pos += W){
                    ll val = dp[pos] - k * V;
                    // drop out‐of‐window
                    while (!dq.empty() && k - dq.front().second > K)
                        dq.pop_front();
                    // maintain decreasing dq by val
                    while (!dq.empty() && dq.back().first <= val)
                        dq.pop_back();
                    dq.emplace_back(val, k);
                    // front of dq is best; restore value
                    dp[pos] = dq.front().first + k * V;
                }
            }
        }
    }

    cout << dp[S] << "\n";
    return 0;
}

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