Submission #674294

#	Time	Username	Problem	Language	Result	Execution time	Memory
674294		ThinGarfield	Knapsack (NOI18_knapsack)	C++11	100 / 100	204 ms	43096 KiB

knapsack

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
#define mp make_pair
#define F first
#define S second

constexpr int maxs = 2e3 + 5;

int n, s;

vector<pii> items[maxs];  // items[i] = all items (val, ct) with weight i, sort by val
ll vadd[maxs][maxs];      // vadd[i][j] = value added by taking j items of weight i
ll dp[maxs][maxs];        // dp[i][j] = best value from i-sized basket w/ only items of weight <= j

int main() {
  //   ios_base::sync_with_stdio(false);
  //   cin.tie(NULL);

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

  for (int i = 1; i <= s; i++) {
    sort(items[i].rbegin(), items[i].rend());
    int ct = 1;
    for (pii it : items[i]) {
      for (int j = 0; j < it.S && ct <= s / i; j++, ct++) {
        vadd[i][ct] = vadd[i][ct - 1] + it.F;
      }
    }
    // cout << i << " : ";
    // for (int j = 0; j <= ct; j++) {
    //   cout << vadd[i][j] << ' ';
    // }
    // cout << '\n';
  }

  for (int i = 1; i <= s; i++) {
    for (int j = 1; j <= s; j++) {
      dp[i][j] = dp[i][j - 1];
      for (int k = 1; j * k <= i && vadd[j][k] != 0; k++) {
        dp[i][j] = max(dp[i][j], dp[i - j * k][j - 1] + vadd[j][k]);
      }
      // cout << dp[i][j] << ' ';
    }
    // cout << '\n';
  }

  cout << dp[s][s] << '\n';

  return 0;
}

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