Submission #385704

#	Time	Username	Problem	Language	Result	Execution time	Memory
385704		mohamedsobhi777	Tram (CEOI13_tram)	C++14	25 / 100	197 ms	23124 KiB

tram

#include <bits/stdc++.h>

using namespace std;

#define vi vector<int>
#define vll vector<ll>
#define vii vector<pair<int, int>>
#define pii pair<int, int>
#define pll pair<ll, ll>
#define loop(_) for (int __ = 0; __ < (_); ++__)
#define pb push_back
#define f first
#define s second
#define sz(_) ((int)_.size())
#define all(_) _.begin(), _.end()
#define lb lower_bound
#define ub upper_bound

using ll = long long;
using ld = long double;

const int N = 2e5 + 7;
const ll mod = 1e9 + 7;

int n, m;
int vis[N][2];
int xs[N], ys[N];
multiset<int> mul;

set<pii> rst, al;
set<pair<ll, pii>> gt;

ll calc(int x, int y, int l = -1, int r = -1)
{
       ll ret = 1e18;
       if (mul.empty())
              return ret;
       auto eval = [&](int u) -> void {
              for (int i = 0; i < 2; ++i)
              {
                     if (u >= 0 && u < n && vis[u][i])
                     {
                            ret = min(ret, 1ll * (u - x) * (u - x) + 1ll * (i - y) * (i - y));
                     }
              }
       };
       if (l == -1)
       {

              auto it = mul.lb(x);
              if (it != mul.end())
                     eval(*it);
              if (it != mul.begin())
                     eval(*(--it));
       }
       else
       {
              eval(l - 1);
              eval(r + 1);
       }
       return ret;
}

map<pii, ll> db;

pair<ll, pii> solve(int x, int y)
{
       ll Min = 0;
       int wx = -1, wy = -1;
       int mi = (x + y) >> 1;
       for (auto mid : {mi, mi + 1})
              for (int i = 0; i < 2; ++i)
              {
                     if (mid < x || mid > y)
                            continue;
                     ll w = calc(mid, i, x, y);
                     if (w > Min || (w == Min && make_pair(mid, i) < make_pair(wx, wy)))
                     {
                            Min = w;
                            wx = mid, wy = i;
                     }
              }
       return {Min, {wx, wy}};
}

void Insert(int x, int y)
{
       rst.insert({x, y});
       gt.insert({-solve(x, y).f, {x, y}});
       db[{x, y}] = -solve(x, y).f;
}

void Erase(int x, int y)
{
       rst.erase({x, y});
       gt.erase({db[{x, y}], {x, y}});
}

int main()
{
       ios_base::sync_with_stdio(0);
       cin.tie(0);
#ifndef ONLINE_JUDGE
#endif
       cin >> n >> m;
       for (int i = 0; i < n; ++i)
       {
              al.insert({i, 0}), al.insert({i, 1});
       }
       Insert(0, n - 1);
       for (int i = 0; i < m; ++i)
       {
              char c;
              cin >> c;
              if (c == 'E')
              {
                     ll Min = 0;
                     int wx = 0, wy = 0;
                     if (sz(gt))
                     {
                            vii vc = {{0, 0}, {0, 1}, {n - 1, 0}, {n - 1, 1}};
                            for (auto u : vc)
                            {
                                   ll sc = calc(u.f, u.s);
                                   if (sc > Min)
                                          Min = sc, wx = u.f, wy = u.s;
                            }

                            auto it = gt.begin();
                            int lhs = (*it).s.f, rhs = (*it).s.s;
                            pair<ll, pii> sol = solve(lhs, rhs);
                            if (sol.f > Min || (sol.f == Min && sol.s < make_pair(wx, wy)))
                            {
                                   Min = sol.f;
                                   wx = sol.s.f, wy = sol.s.s;
                            }
                            if (Min <= 1)
                            {
                                   auto bg = al.begin();
                                   wx = (*bg).f, wy = (*bg).s;
                            }
                     }
                     else if (!sz(mul))
                            ;
                     else
                     {
                            auto bg = al.begin();
                            wx = (*bg).f, wy = (*bg).s;
                     }

                     xs[i] = wx, ys[i] = wy;
                     vis[wx][wy] = 1;
                     auto it = rst.lb({wx + 1, -1});
                     mul.insert(wx);

                     if (it != rst.begin())
                     {
                            --it;
                            if (wx >= (*it).f && wx <= (*it).s)
                            {
                                   pii u = *it;
                                   int x = u.f, y = u.s;
                                   Erase(x, y);
                                   if (x <= wx - 1)
                                          Insert(x, wx - 1);
                                   if (wx + 1 <= y)
                                          Insert(wx + 1, y);
                            }
                     }

                     al.erase({wx, wy});
                     cout << ++wx << " " << ++wy << "\n";
              }
              else
              {
                     int p;
                     cin >> p;
                     --p;

                     mul.erase(mul.find(xs[p]));
                     vis[xs[p]][ys[p]] = 0;
                     al.insert({xs[p], ys[p]});
                     if (vis[xs[p]][0] == vis[xs[p]][1])
                     {
                            int nx = xs[p], ny = xs[p];
                            auto it = rst.lb({xs[p], -1});
                            pii del = {-1, -1};
                            if (it != rst.end() && (*it).f == ny + 1)
                            {
                                   ny = (*it).s;
                                   del = {(*it).f, (*it).s};
                            }
                            if (it != rst.begin())
                            {
                                   --it;
                                   if ((*it).s == nx - 1)
                                   {
                                          nx = (*it).f;
                                          Erase((*it).f, (*it).s);
                                   }
                            }
                            if (~del.f)
                                   Erase(del.f, del.s);
                            Insert(nx, ny);
                     }
              }
       }
       return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 15 / 15
• Subtask 3: 0 / 10
• Subtask 4: 0 / 10
• Subtask 5: 0 / 10
• Subtask 6: 0 / 10
• Subtask 7: 0 / 15
• Subtask 8: 0 / 20