Submission #989607

#	Time	Username	Problem	Language	Result	Execution time	Memory
989607		aykhn	Palembang Bridges (APIO15_bridge)	C++17	100 / 100	76 ms	8820 KiB

bridge

#include <bits/stdc++.h>
 
using namespace std;
 
#define int long long
#define inf 0x3F3F3F3F3F3F3F3F
 
signed main()
{
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int k, n, S = 0;
  cin >> k >> n;
  vector<array<int, 2>> v;
  for (int i = 0; i < n; i++)
  {
    char a, b;
    int l, r;
    cin >> a >> l >> b >> r;
    if (l > r) swap(l, r);
    if (a == b) S += r - l;
    else v.push_back({l, r});
  }
  if (v.empty())
  {
    cout << S << '\n';
    return 0;
  }
  n = v.size();
  sort(v.begin(), v.end(), [&](const array<int, 2> &a, const array<int, 2> &b)
  {
    return a[0] + a[1] < b[0] + b[1];
  });
  vector<int> bs(n, 0), bp(n, 0);
  priority_queue<int> L;
  priority_queue<int, vector<int>, greater<int>> R;
  int sL = 0, sR = 0;
  for (int i = 0; i < n; i++)
  {
    L.push(v[i][0]), L.push(v[i][1]);
    sL += v[i][0] + v[i][1];
    while (!L.empty() && !R.empty() && L.top() > R.top()) R.push(L.top()), sR += L.top(), sL -= L.top(), L.pop();
    while (L.size() > R.size()) R.push(L.top()), sR += L.top(), sL -= L.top(), L.pop();
    while (L.size() < R.size()) L.push(R.top()), sL += R.top(), sR -= R.top(), R.pop();
    bp[i] = sR - sL;
  }
  while (!L.empty()) L.pop();
  while (!R.empty()) R.pop();
  sL = sR = 0;
  for (int i = n - 1; i >= 0; i--)
  {
    L.push(v[i][0]), L.push(v[i][1]);
    sL += v[i][0] + v[i][1];
    while (!L.empty() && !R.empty() && L.top() > R.top()) R.push(L.top()), sR += L.top(), sL -= L.top(), L.pop();
    while (L.size() > R.size()) R.push(L.top()), sR += L.top(), sL -= L.top(), L.pop();
    while (L.size() < R.size()) L.push(R.top()), sL += R.top(), sR -= R.top(), R.pop();
    bs[i] = sR - sL;
  }
  if (k == 1 || v.size() == 1) cout << bp[n - 1] + S + n << '\n';
  else
  {
    int res = bp[n - 1];
    for (int i = 0; i + 1 < n; i++) res = min(res, bp[i] + bs[i + 1]);
    cout << res + S + n << '\n';
  }
}

• Subtask 1: 8 / 8
• Subtask 2: 14 / 14
• Subtask 3: 9 / 9
• Subtask 4: 32 / 32
• Subtask 5: 37 / 37