제출 #281673

#제출 시각아이디문제언어결과실행 시간메모리
281673VimmerSky Walking (IOI19_walk)C++14
10 / 100
2596 ms1048580 KiB
#include "walk.h"
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

#define F first
#define S second
#define sz(x) int(x.size())
#define pb push_back
#define N 100001

using namespace std;
using namespace __gnu_pbds;

typedef long long ll;
typedef pair <int, int> ptr;
typedef array <int, 3> a3;

vector <vector <int> > g;

vector <a3 > edge;

vector <int> nums[N], who[N], db[N], del[N];

vector <ll> dst;

vector <char> mk;

gp_hash_table <int, int> idr[N];

void add(int a, int b, int cost)
{
    g[a].pb(sz(edge));

    g[b].pb(sz(edge));

    edge.pb({a, b, cost});
}

ll min_distance(vector<int> x, vector<int> h, vector<int> l, vector<int> r, vector<int> y, int s, int to)
{
    if (s == to) return 0;

    int n = sz(x);

    int m = sz(l);

    set <pair <int, int> > st; st.clear();

    for (int j = 0; j < m; j++)
        {db[l[j]].pb(j); del[r[j]].pb(j);}

    for (int i = 0; i < n; i++)
    {
        for (auto j : db[i])
            st.insert({y[j], j});

        auto it = st.upper_bound(ptr(h[i], 1e9));

        if (it != st.begin())
        {
            it--;

            while (1)
            {
                nums[i].pb((*it).S);

                if (it == st.begin()) break;

                it--;
            }
        }
        for (auto j : del[i])
            st.erase({y[j], j});
    }

    int id = 0;

    ll ans = 1e18;

    set <pair <ll, int> > str;

    set <pair <int, int> > se; se.clear();

    for (int i = 0; i < n; i++)
      for (auto j : nums[i])
      {
          if (i == to) se.insert({id, y[j]});

          idr[i][j] = id++;

          g.emplace_back();

          mk.pb('a');

          dst.pb(-1);

          for (auto jr : nums[i])
          {
              if (jr == j) break;

              add(id - 1, idr[i][jr], abs(y[jr] - y[j]));
          }

          if (s == i) {dst[id - 1] = 0; str.insert({y[j], id - 1});}
      }

    for (int i = 0; i < n; i++)
        for (auto j : nums[i])
        {
            for (auto I : who[j])
              add(idr[i][j], idr[I][j], abs(x[i] - x[I]));

            who[j].pb(i);
        }

    while (sz(str))
    {
        pair <ll, int> pt = *str.begin(); str.erase(str.begin());

        if (mk[pt.S] == 'b') continue;

        mk[pt.S] = 'b';

        if (pt.F >= ans) return ans;

        auto it = se.upper_bound(ptr(pt.S, 1e9 + 1e9));

        if (it != se.begin())
        {
            it--;

            if ((*it).F == pt.S) {ans = min(ans, pt.F + (*it).S); se.erase(it); if (sz(se) == 0) return ans;}
        }

        for (auto ip : g[pt.S])
        {
            a3 itr = edge[ip];

            ll s = pt.F + itr[2];

            if (itr[0] == pt.S) swap(itr[0], itr[1]);

            if (dst[itr[0]] != - 1 && dst[itr[0]] <= s) continue;

            if (ans <= s) continue;

            dst[itr[0]] = s;

            str.insert({s, itr[0]});
        }
    }

    if (ans == 1e18) return -1;

	return ans;
}


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