Submission #1163010

#	Time	Username	Problem	Language	Result	Execution time	Memory
1163010		avighna	Knapsack (NOI18_knapsack)	C++20	100 / 100	165 ms	246508 KiB

knapsack

#include <bits/stdc++.h>

typedef long long ll;

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

  ll s, n;
  std::cin >> s >> n;
  std::vector<std::vector<std::pair<ll, ll>>> items(2001);
  for (ll i = 0, v, w, k; i < n; ++i) {
    std::cin >> v >> w >> k;
    items[w].push_back({v, k});
  }
  // for the same weight, prefer more valauble items
  for (auto &i : items) {
    std::sort(i.rbegin(), i.rend());
  }
  // actual items: O(s log s) many
  std::vector<std::pair<ll, ll>> a;
  for (ll w = 1; w <= 2000; ++w) {
    ll max = 2000 / w;
    for (auto [v, k] : items[w]) {
      while (k--) {
        max--;
        a.push_back({w, v});
        if (max == 0) {
          break;
        }
      }
      if (max == 0) {
        break;
      }
    }
  }

  std::vector<std::vector<ll>> dp(a.size() + 1, std::vector<ll>(s + 1));
  for (ll i = a.size(); i >= 0; --i) {
    for (ll j = s; j >= 0; --j) {
      if (i == a.size()) {
        dp[i][j] = 0;
        continue;
      }
      dp[i][j] = dp[i + 1][j];
      if (j + a[i].first <= s) {
        dp[i][j] = std::max(dp[i][j], dp[i + 1][j + a[i].first] + a[i].second);
      }
    }
  }
  std::cout << dp[0][0] << '\n';
}

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