Submission #842653

#	Time	Username	Problem	Language	Result	Execution time	Memory
842653		flashmt	Closing Time (IOI23_closing)	C++17	59 / 100	1061 ms	28040 KiB

closing

#include "closing.h"
#ifdef LOCAL
#include "Debug.h"
#else
#define debug(...) 42
#endif
#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 5;
const long long oo = (1LL << 62) - 10;

int n;
vector<pair<int, int>> a[N];
vector<int> idPath, idTree, trees[N];

vector<long long> bfs(int s)
{
  vector<long long> dist(n, -1);
  queue<int> q;
  dist[s] = 0;
  q.push(s);
  while (!empty(q))
  {
    int x = q.front();
    q.pop();
    for (auto [y, w] : a[x])
      if (dist[y] < 0)
      {
        dist[y] = dist[x] + w;
        q.push(y);
      }
  }
  return dist;
}

int findPath(int x, int goal, int par, vector<int> &path)
{
  path.push_back(x);
  if (x == goal)
    return 1;
  for (auto [y, _] : a[x])
    if (y != par)
    {
      if (findPath(y, goal, x, path))
        return 1;
    }
  path.pop_back();
  return 0;
}

void dfs(int x)
{
  trees[idTree[x]].push_back(x);
  for (auto [y, _] : a[x])
    if (idTree[y] < 0)
    {
      idTree[y] = idTree[x];
      dfs(y);
    }
}

int max_score(int N, int A, int B, long long budget, vector<int> U, vector<int> V, vector<int> W)
{
  n = N;
  for (int i = 0; i < n; i++)
    a[i].clear();
  for (int i = 0; i < size(U); i++)
  {
    a[U[i]].push_back({V[i], W[i]});
    a[V[i]].push_back({U[i], W[i]});
  }

  auto distA = bfs(A);
  auto distB = bfs(B);
  auto distAB = distA[B];

  if (distAB > budget * 2)
  {
    vector<long long> allDists = distA;
    for (auto d : distB)
      allDists.push_back(d);
    sort(begin(allDists), end(allDists));
    int ans = 0;
    for (auto d : allDists)
      if (d <= budget)
      {
        ans++;
        budget -= d;
      }
    return ans;
  }

  // O(n^3)
  vector<int> path;
  findPath(A, B, -1, path);
  idPath.assign(n, -1);
  idTree.assign(n, -1);
  int len = size(path);
  for (int i = 0; i < len; i++)
  {
    idPath[path[i]] = idTree[path[i]] = i;
    trees[i].clear();
  }
  for (int x : path)
    dfs(x);

  int ans = 0;
  for (int l = 0; l < len; l++)
  {
    vector<long long> f(n * 2 + 1, oo);
    f[0] = 0;
    int cnt = 0;
    for (int r = len - 1; r >= 0; r--)
    {
      long long curCost = 0;
      int curAns = 0;

      vector<long long> c1;
      for (int i = 0; i < n; i++)
      {
        if (idTree[i] > l && idTree[i] < r)
          continue;

        if (idTree[i] < r) // A
        {
          if (idPath[i] < 0) c1.push_back(distA[i]);
          else curCost += distA[i], curAns++;
        }
        else if (idTree[i] > l) // B
        {
          if (idPath[i] < 0) c1.push_back(distB[i]);
          else curCost += distB[i], curAns++;
        }
        else // AB
        {
          if (idPath[i] >= 0)
            curCost += max(distA[i], distB[i]), curAns += 2;
        }
      }

      if (curCost > budget)
        break;

      long long rem = budget - curCost;

      // add new tree to f
      if (r <= l)
      {
        for (int x : trees[r])
          if (idPath[x] < 0)
          {
            auto minDist = min(distA[x], distB[x]);
            auto maxDist = max(distA[x], distB[x]);
            for (int i = cnt; i >= 0; i--)
            {
              f[i + 1] = min(f[i + 1], f[i] + minDist);
              f[i + 2] = min(f[i + 2], f[i] + maxDist);
            }
            cnt += 2;
          }
      }

      sort(begin(c1), end(c1));
      vector<long long> costFor(size(c1) + 1);
      for (int i = 0; i < size(c1); i++)
        costFor[i + 1] = costFor[i] + c1[i];

      for (int i = 0; i <= cnt; i++)
        if (f[i] > rem) break;
        else
        {
          int u = upper_bound(begin(costFor), end(costFor), rem - f[i]) - begin(costFor);
          ans = max(ans, curAns + i + u - 1);
        }
    }
  }

  return ans;
}

Compilation message (stderr)

closing.cpp: In function 'int max_score(int, int, int, long long int, std::vector<int>, std::vector<int>, std::vector<int>)':
closing.cpp:67:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   67 |   for (int i = 0; i < size(U); i++)
      |                   ~~^~~~~~~~~
closing.cpp:165:25: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  165 |       for (int i = 0; i < size(c1); i++)
      |                       ~~^~~~~~~~~~

• Subtask 0: 0 / 0
• Subtask 1: 8 / 8
• Subtask 2: 9 / 9
• Subtask 3: 12 / 12
• Subtask 4: 0 / 14
• Subtask 5: 9 / 9
• Subtask 6: 11 / 11
• Subtask 7: 10 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 17