Submission #1265597

#	Time	Username	Problem	Language	Result	Execution time	Memory
1265597		tochika	Knapsack (NOI18_knapsack)	C++20	100 / 100	34 ms	1608 KiB

knapsack

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

#define IN "iii.txt"
#define OUT "ooo.txt"
#define MULTI_TEST 0

const int MOD = 1e9 + 7;
const int MAX = 1e8 + 5;
const lint LMAX = 1e18;

void solve() {
    int s, n;
    cin >> s >> n;

    vector<vector<pair<int, int>>> grouped(s + 1);

    for (int i = 0; i < n; i++) {
        int v, w, k;
        cin >> v >> w >> k;

        if (w > s)
            continue;

        grouped[w].push_back({v, k});
    }

    vector<lint> dp(s + 1, 0);

    for (int w = 1; w <= s; w++) {
        if (grouped[w].empty())
            continue;

        vector<int> best_w;
        int limit = s / w;

        sort(grouped[w].begin(), grouped[w].end(), [](pair<int, int>& a, pair<int, int>& b){
            return a.first > b.first;
        });

        for (auto items : grouped[w]) {
            int v = items.first;
            int k = items.second;

            for (int i = 0; i < k; i++) {
                if (best_w.size() >= limit)
                    break;
                best_w.push_back(v);
            }

            if (best_w.size() >= limit)
                break;
        }

        for (int v_val : best_w) {
            for (int c = s; c >= w; c--) {
                dp[c] = max(dp[c], dp[c - w] + v_val);
            }
        }
    }

    cout << *max_element(dp.begin(), dp.end());
}

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

    if (fopen(IN, "r")) {
        freopen(IN, "r", stdin);
        freopen(OUT, "w", stdout);
    }

    int t = 1;
    if (MULTI_TEST) {
        cin >> t;
    }

    for (int i = 1; i <= t; i++) {
        solve();
        cout << '\n';
    }

    return 0;
}

Compilation message (stderr)

knapsack.cpp: In function 'int main()':
knapsack.cpp:71:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   71 |         freopen(IN, "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~
knapsack.cpp:72:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   72 |         freopen(OUT, "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~

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