Submission #1088630

#	Time	Username	Problem	Language	Result	Execution time	Memory
1088630		shidou26	Knapsack (NOI18_knapsack)	C++14	100 / 100	274 ms	4036 KiB

knapsack

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

#define endl '\n'
#define all(v) v.begin(), v.end()

typedef long long ll;
typedef pair<int, int> ii;
typedef pair<ll, int> li;

const int N = 2008;

int s, n;

map<int, vector<ii>> items;

void prepare() {

}

void input() {
    cin >> s >> n;

    for(int i = 1; i <= n; i++) {
        int v, w, k; cin >> v >> w >> k;
        items[w].push_back(ii(v, k));
    }
}

void process() {
    vector<ll> dp, prev_dp;
    prev_dp.resize(s + 1, -1e18); dp.resize(s + 1, -1e18);
    prev_dp[0] = 0;
    ll best = 0;
    for(pair<int, vector<ii>> p : items) {
        sort(all(p.second), greater<ii>());
        for(int j = 0; j <= s; j++) {
            dp[j] = prev_dp[j];
            int total = 0; ll profit = 0;
            for(int k = 0; k < (int)p.second.size(); k++) {
                int v, a; tie(v, a) = p.second[k];
                while(a > 0 && (total + 1) * p.first <= j) {
                    total++; profit += v; a--;
                    dp[j] = max(dp[j], prev_dp[j - total * p.first] + profit);
                }
            }
            best = max(best, dp[j]);
        }
        prev_dp = dp;
    }
    cout << best << endl;
}

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

    #define task "grouping"
    if(fopen(task".INP", "r")) {
        freopen(task".INP", "r", stdin);
        freopen(task".OUT", "w", stdout);
    }

    prepare();

    int testcase = 1; // cin >> testcase;
    for(int i = 1; i <= testcase; i++) {
        input();
        process();
    }

    return 0;
}

Compilation message (stderr)

knapsack.cpp: In function 'int main()':
knapsack.cpp:60:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   60 |         freopen(task".INP", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
knapsack.cpp:61:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   61 |         freopen(task".OUT", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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