Submission #949504

#	Time	Username	Problem	Language	Result	Execution time	Memory
949504		Github	Knapsack (NOI18_knapsack)	C++17	73 / 100	1062 ms	27572 KiB

knapsack

#include <bits/stdc++.h>
using namespace std;
 
typedef long long ll;
typedef struct {bool unlimited; ll w, t;} platedata;
 
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
 
    int l, k;
    cin >> l >> k;
 
    vector<platedata> plates;
    while (k--) {
        ll n, w, t;
        cin >> w >> t >> n;
        if ((n+1) * t > l) {
            // We have effectively infinity of these plates
            plates.push_back({true, w, t});
        } else {
            // Fuse plates into powers of 2 for efficiency
            int used = 0;
            for (int mult = 1; mult * 2 <= n; mult *= 2) {
                used += mult;
                plates.push_back({false, w*mult, t*mult});
            }
            int finalMult = n - used;
            plates.push_back({false, w*finalMult, t*finalMult});
        }
    }
 
    vector<ll> dpOld(l+1,0);
    for (auto [unlimited, w, t] : plates) {
        vector<ll> dpNew = {0};
        for (int j = 1; j <= l; j++) {
            ll bestimate = dpOld[j];
            if (t <= j) {
                vector<ll> &smallerCase = unlimited ? dpNew : dpOld;
                bestimate = max(bestimate, smallerCase[j-t] + w);
            }
            dpNew.push_back(bestimate);
        }
        dpOld = dpNew;
    }
 
    cout << dpOld[l] << endl;
    return 0;
}

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