Submission #761407

#	Time	Username	Problem	Language	Result	Execution time	Memory
761407		MinaRagy06	Sky Walking (IOI19_walk)	C++17	10 / 100	4066 ms	260332 KiB

walk

#include <bits/stdc++.h>
using namespace std;
using ll = long long;

vector<int> intersect[100'005];
vector<pair<int, int>> adj[100'005];
vector<ll> dist[100'005];
vector<int> idx[100'005];
const ll INF = 1e18;
ll min_distance(vector<int> x, vector<int> h, vector<int> l, vector<int> r, vector<int> y, int s, int g) {
    auto st = chrono::steady_clock::now().time_since_epoch().count();
    int n = x.size(), m = l.size();
    array<int, 3> skywalks[m];
    for (int i = 0; i < m; i++) {
        skywalks[i] = {y[i], l[i], r[i]};
    }
    sort(skywalks, skywalks + m);
    for (int i = m - 1; i >= 0; i--) {
        y[m - 1 - i] = skywalks[i][0];
        l[m - 1 - i] = skywalks[i][1];
        r[m - 1 - i] = skywalks[i][2];
    }
    array<int, 3> buildings[n];
    for (int i = 0; i < n; i++) {
        buildings[i] = {h[i], x[i], i};
    }
    int actual[n];
    sort(buildings, buildings + n);
    bool oks = 0, okg = 0;
    for (int i = 0; i < n; i++) {
        h[i] = buildings[i][0];
        x[i] = buildings[i][1];
        actual[i] = buildings[i][2];
        if (!oks && s == actual[i]) {
            s = i;
            oks = 1;
        }
        if (!okg && g == actual[i]) {
            g = i;
            okg = 1;
        }
    }
    y.push_back(0);
    idx[s].push_back(m);
    dist[s].push_back(INF);
    int ptr = n - 1;
    set<array<int, 3>> gud;
    for (int i = 0; i < m; i++) {
        while (ptr >= 0 && y[i] <= h[ptr]) {
            gud.insert({actual[ptr], ptr, h[ptr]});
            ptr--;
        }
        auto it = gud.lower_bound({l[i], 0, 0});
        while (it != gud.end() && (*it)[0] <= r[i]) {
            intersect[i].push_back((*it)[1]);
            it++;
        }
        for (int k = 0; k < intersect[i].size(); k++) {
            dist[intersect[i][k]].push_back(INF);
            idx[intersect[i][k]].push_back(i);
        }
        for (int k = 0; k < intersect[i].size(); k++) {
            if (k + 1 < intersect[i].size()) {
                adj[intersect[i][k]].push_back({intersect[i][k + 1], idx[intersect[i][k + 1]].size() - 1});
            }
            if (k - 1 >= 0) {
                adj[intersect[i][k]].push_back({intersect[i][k - 1], idx[intersect[i][k - 1]].size() - 1});
            }
        }
    }
    priority_queue<pair<ll, pair<int, int>>> pq;
    pq.push({0, {s, 0}});
    while (pq.size()) {
        ll d = -pq.top().first;
        int i = pq.top().second.first;
        int j = pq.top().second.second;
        pq.pop();
        if (d > dist[i][j]) continue;
        j = y[idx[i][j]];
        for (auto [nxt, nxth] : adj[i]) {
            ll newd = d + abs(x[nxt] - x[i]) + abs(j - y[idx[nxt][nxth]]);
            if (newd < dist[nxt][nxth]) {
                dist[nxt][nxth] = newd;
                pq.push({-newd, {nxt, nxth}});
            }
        }
    }
    // cout << s << ' ' << g << '\n';
    ll ans = INF;
    for (int i = 0; i < dist[g].size(); i++) {
        ans = min(ans, dist[g][i] + y[idx[g][i]]);
    }
    // auto en = chrono::steady_clock::now().time_since_epoch().count();
    // cout << (en - st) / 1e9 << '\n';
    if (ans >= INF) return -1;
    return ans;
}
//int main() {
//    ios_base::sync_with_stdio(0), cin.tie(0);
//    int N, M;
//    cin >> N >> M;
//    vector<int> X(N), H(N);
//    for (int i = 0; i < N; i++) {
//        cin >> X[i] >> H[i];
//    }
//    vector<int> L(M), R(M), Y(M);
//    for (int i = 0; i < M; i++) {
//        cin >> L[i] >> R[i] >> Y[i];
//    }
//    int S, G;
//    cin >> S >> G;
//    cout << min_distance(X, H, L, R, Y, S, G) << '\n';
//    return 0;
//}

Compilation message (stderr)

walk.cpp: In function 'll min_distance(std::vector<int>, std::vector<int>, std::vector<int>, std::vector<int>, std::vector<int>, int, int)':
walk.cpp:58:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   58 |         for (int k = 0; k < intersect[i].size(); k++) {
      |                         ~~^~~~~~~~~~~~~~~~~~~~~
walk.cpp:62:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   62 |         for (int k = 0; k < intersect[i].size(); k++) {
      |                         ~~^~~~~~~~~~~~~~~~~~~~~
walk.cpp:63:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   63 |             if (k + 1 < intersect[i].size()) {
      |                 ~~~~~~^~~~~~~~~~~~~~~~~~~~~
walk.cpp:90:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   90 |     for (int i = 0; i < dist[g].size(); i++) {
      |                     ~~^~~~~~~~~~~~~~~~
walk.cpp:11:10: warning: unused variable 'st' [-Wunused-variable]
   11 |     auto st = chrono::steady_clock::now().time_since_epoch().count();
      |          ^~

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