Submission #434234

#	Time	Username	Problem	Language	Result	Execution time	Memory
434234		emil_physmath	Sky Walking (IOI19_walk)	C++17	24 / 100	1769 ms	361008 KiB

walk

#define BUGO(x) cerr << #x << " -> " << (x) << endl;
#include "walk.h"
#include <algorithm>
#include <iostream>
#include <numeric>
#include <vector>
#include <queue>
#include <set>
#include <map>
using namespace std;
using llong = long long;

vector<pair<int, int>> nei[6900'000];
llong dist[6900'000];

llong Dijkstra(int s, int e)
{
    const llong inf = 69'000'000'000'000'000LL;
    fill(dist, dist + 6900'000, inf);
    priority_queue<pair<llong, int>> q;
    q.push({dist[s] = 0, s});
    while (q.size())
    {
        int v = q.top().second;
        llong d = -q.top().first;
        q.pop();
        if (dist[v] != d) continue;
        for (auto to: nei[v])
            if (d + to.second < dist[to.first])
                q.push({-(dist[to.first] = d + to.second), to.first});
    }
    return dist[e] == inf ? -1 : dist[e];
}

map<int, int> nodeOf[100'000];
long long min_distance(std::vector<int> x, std::vector<int> y, std::vector<int> l, std::vector<int> r,
std::vector<int> h, int s, int e) {
    int n = x.size();
    int m = l.size();
    int nodes = 0;
    for (int i = 0; i < n; ++i)
        nodeOf[i][y[i]] = nodes++;
    nodeOf[s][0] = nodes++;
    nodeOf[e][0] = nodes++;
    bool smallTest = (n <= 50 && m <= 50) || y != vector<int>(n, y[0]);
    vector<int> towers(n);
    iota(towers.begin(), towers.end(), 0);
    sort(towers.begin(), towers.end(), [&](int l, int r) {
        return y[l] < y[r];
    });
    vector<int> bridges(m);
    iota(bridges.begin(), bridges.end(), 0);
    sort(bridges.begin(), bridges.end(), [&](int l, int r) {
        return h[l] < h[r];
    });
    set<int> activeTowers;
    for (int tch = m - 1; tch >= 0; --tch)
    {
        int j = bridges[tch];
        while (towers.size() && y[towers.back()] >= h[j]) {
            activeTowers.insert(towers.back());
            towers.pop_back();
        }
        int lt = -1;
        for (auto it = activeTowers.lower_bound(l[j]); it != activeTowers.end() && *it <= r[j]; )
        {
            int i = *it;
            if (!nodeOf[i].count(h[j]))
                nodeOf[i][h[j]] = nodes++;
            if (lt != -1) {
                int u = nodeOf[i][h[j]];
                int v = nodeOf[lt][h[j]];
                nei[u].push_back({v, x[i] - x[lt]});
                nei[v].push_back({u, x[i] - x[lt]});
            }
            lt = i;
            if (smallTest)
                ++it;
            else if (*it == l[j])
                it = activeTowers.lower_bound(r[j]);
            else
                break;
        }
    }
    for (int i = 0; i < n; ++i)
    {
        int ltHei = -1;
        for (auto [hei, node]: nodeOf[i])
        {
            if (ltHei != -1) {
                int u = nodeOf[i][ltHei];
                int v = node;
                nei[u].push_back({v, hei - ltHei});
                nei[v].push_back({u, hei - ltHei});
            }
            ltHei = hei;
        }
    }
    return Dijkstra(n, n + 1);
}

• Subtask 1: 10 / 10
• Subtask 2: 14 / 14
• Subtask 3: 0 / 15
• Subtask 4: 0 / 18
• Subtask 5: 0 / 43