제출 #1164238

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1164238		ChottuF	Knapsack (NOI18_knapsack)	C++20	100 / 100	53 ms	5448 KiB

knapsack

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

const int MAX_N = 1e6 + 15;

#define ll long long

ll numItems, capacity;
ll value[MAX_N];
ll weight[MAX_N];
ll itemCount[MAX_N];

vector<pair<ll, int>> itemsByWeight[4000];

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    cin >> capacity >> numItems;

    for (int i = 0; i < numItems; i++)
        cin >> value[i] >> weight[i] >> itemCount[i];

    ll maxItemCount = *max_element(itemCount, itemCount + numItems);

    if (numItems == 1) {
        cout << value[0] * min(capacity / weight[0], itemCount[0]) << '\n';
    } else if (1 <= numItems && numItems <= 100 && maxItemCount <= 10) {
        ll dp[4000];
        memset(dp, 0, sizeof dp);

        for (int i = 0; i < numItems; i++) {
            for (int w = capacity; w >= 0; w--) {
                for (ll j = 1; j <= itemCount[i]; j++) {
                    if (w + j * weight[i] > capacity)
                        break;
                    if ((dp[w] > 0 || w == 0)) {
                        dp[w + j * weight[i]] = max(dp[w + j * weight[i]], dp[w] + j * value[i]);
                    }
                }
            }
        }
        ll ans = 0;
        for (int i = 1; i <= capacity; i++)
            ans = max(ans, dp[i]);
        cout << ans << '\n';
    } else {
        ll dp[4000];
        ll ans = 0;
        memset(dp, 0, sizeof dp);

        for (int i = 0; i < numItems; i++)
            itemsByWeight[weight[i]].push_back({value[i], itemCount[i]});

        for (int i = 1; i <= capacity; i++) {
            if (itemsByWeight[i].size() == 0)
                continue;
            sort(itemsByWeight[i].begin(), itemsByWeight[i].end(), greater<pair<int, int>>());

            int id = 0;

            for (int j = 1; j * i <= capacity; j++) {
                if (id >= itemsByWeight[i].size())
                    break;
                for (int w = capacity; w >= 0; w--) {
                    if ((w == 0 || dp[w] > 0) && w + i <= capacity) {
                        dp[w + i] = max(dp[w + i], dp[w] + itemsByWeight[i][id].first);
                    }
                }
                --itemsByWeight[i][id].second;
                if (itemsByWeight[i][id].second == 0)
                    id++;
            }
        }

        for (int i = 1; i <= capacity; i++)
            ans = max(ans, dp[i]);
        cout << ans << '\n';
    }

    return 0;
}

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