Submission #573168

#TimeUsernameProblemLanguageResultExecution timeMemory
573168600MihneaRoad Closures (APIO21_roads)C++17
14 / 100
2099 ms29628 KiB
#include <bits/stdc++.h>
#include "roads.h"


using namespace std;

typedef long long ll;

vector<ll> minimum_closure_costs(int n, vector<int> Uedges, vector<int> Vedges, vector<int> Wedges) {

  const ll inf = (ll) 1e18 + 7;

  assert((int) Uedges.size() == n - 1);
  assert((int) Vedges.size() == n - 1);
  assert((int) Wedges.size() == n - 1);

  vector<vector<pair<int, int>>> g(n);
  vector<int> md(n, 0);
  vector<ll> dp_take(n, -inf);
  vector<ll> dp_not(n, -inf);

  int maxDeg;

  vector<int> sub(n), value(n, 0);
  for (int i = 0; i < n - 1; i++) {
    g[Uedges[i]].push_back({Vedges[i], Wedges[i]});
    g[Vedges[i]].push_back({Uedges[i], Wedges[i]});
  }

  function<void(int, int)> build = [&] (int a, int p) {
    md[a] = (int) g[a].size();
    sub[a] = 1;
    vector<pair<int, int>> kids;
    for (auto &it : g[a]) {
      int b = it.first;
      if (b == p) continue;
      value[b] = it.second;
      kids.push_back(it);
      build(b, a);
      sub[a] += sub[b];
      md[a] = max(md[a], md[b]);
    }
    g[a] = kids;
  };

  function<void(int)> dfs = [&] (int a) {
    if (g[a].empty()) {
      dp_not[a] = 0;
      if (1 <= maxDeg) {
        dp_take[a] = value[a];
      }
      return;
    }

    assert(!g[a].empty());

    int ln = min(md[a], maxDeg);

    vector<ll> best(ln + 1, -inf);
    best[0] = 0;

    for (auto &it : g[a]) {
      int b = it.first;
      ll cost = it.second;
      dfs(b);


      vector<ll> new_best(ln + 1, -inf);

      for (int bef = 0; bef <= ln; bef++) {
        /// don't take it
        new_best[bef] = max(new_best[bef], best[bef] + dp_not[b]);
        /// take it
        if (bef + 1 <= ln) {
          new_best[bef + 1] = max(new_best[bef + 1], best[bef] + dp_take[b]);
        }
      }
      best = new_best;
    }

    for (int d = 0; d <= ln; d++) {
      dp_not[a] = max(dp_not[a], best[d]);
      if (d + 1 <= maxDeg) {
        dp_take[a] = max(dp_take[a], best[d] + value[a]);
      }
    }

  };

  build(0, -1);

  vector<ll> print(n, 0);

  for (maxDeg = 0; maxDeg < n; maxDeg++) {
    for (auto &x : dp_take) x = -inf;
    for (auto &x : dp_not) x = -inf;
    dfs(0);
    print[maxDeg] = dp_not[0];
  }

  {
    ll totalSum = 0;
    for (auto &x : Wedges) {
      totalSum += x;
    }

    for (auto &x : print) {
      x = totalSum - x;
    }
  }
  return print;
}

Compilation message (stderr)

roads.cpp: In lambda function:
roads.cpp:64:10: warning: unused variable 'cost' [-Wunused-variable]
   64 |       ll cost = it.second;
      |          ^~~~
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