Submission #1219285

#	Time	Username	Problem	Language	Result	Execution time	Memory
1219285		spampots	Knapsack (NOI18_knapsack)	C++20	100 / 100	43 ms	1864 KiB

knapsack

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<pii> vpii;

const int MOD = 1e9 + 7;
const int INF = INT_MAX;
const ll LINF = LLONG_MAX;

#define fast ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL)

#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define all(v) v.begin(), v.end()
#define rep(i, a, b) for(int i = a; i < b; ++i)

void solve() {
    int S, N;
    cin >> S >> N;
    vector<vector<pair<int, int>>> items(S+1);
    for(int i = 0; i < N; ++i){
        int v, w, k;
        cin >> v >> w >> k;
        if(w <= S)
            items[w].push_back({v, k});
    } 

    auto st = [&](pii& a, pii& b) -> bool{
        if(a.fi != b.fi)
            return a.fi > b.fi;
        return a.se > b.se;
    };

    for(int i = 1; i <= S; ++i)
        sort(items[i].begin(), items[i].end(), st);

    vector<pair<int, int>> item;
    // in item store the following : wt, price

    for(int i = 1; i <= S; ++i){
        int id = 0;
        int itmct = S / i;
        while(id < (int)items[i].size() && itmct > 0){
            auto [v, k] = items[i][id];
            int use = min(k, itmct);
            for(int j = 0; j < use; ++j)
                item.pb({i, v});
            itmct -= use;
            id++;
        }
    }

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

    for(auto& [wt, val] : item) {
        for(int w = S; w >= wt; --w) {
            dp[w] = max(dp[w], val + dp[w - wt]);
        }
    }
    cout << dp[S] << endl;
}

int main() {
    fast;

    int t = 1;
    while(t--) {
        solve();
    }

    return 0;
}

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