Submission #761441

#	Time	Username	Problem	Language	Result	Execution time	Memory
761441		MinaRagy06	Sky Walking (IOI19_walk)	C++17	10 / 100	4064 ms	502296 KiB

walk

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

struct bheap {
    vector<int> heap, mp;
    vector<ll> val;
    bheap() {}
    bheap(int n) {
        val.assign(n, 1e9);
        mp.assign(n, -1);
    }
    void sink(int pos) {
        while ((pos << 1) + 1 < heap.size()) {
            int l = (pos << 1) + 1, r = (pos << 1) + 2;
            int smallest = l;
            if (r < heap.size() && val[heap[r]] < val[heap[l]]) smallest = r;
            if (val[heap[smallest]] < val[heap[pos]]){
                mp[heap[smallest]] = pos;
                mp[heap[pos]] = smallest;
                swap(heap[pos], heap[smallest]);
            } else {
                break;
            }
            pos = smallest;
        }
    }
    bool swim(int pos) {
        int p = (pos - 1) >> 1;
        if (!(pos && val[heap[p]] > val[heap[pos]])) return 0;
        while (pos&&val[heap[p]]>val[heap[pos]]) {
            mp[heap[p]] = pos;
            mp[heap[pos]] = p;
            swap(heap[p], heap[pos]);
            pos = p;
            p = (pos - 1) >> 1;
        }
        return 1;
    }
    void push(int key, ll value) {
        int pos = heap.size();
        heap.push_back(key);
        mp[key] = pos;
        val[key] = value;
        swim(pos);
    }
    int pop() {
        int n = heap.size(), ret = heap[0];
        mp[heap[0]] = n - 1;
        mp[heap[n - 1]] = 0;
        swap(heap[0], heap[n-1]);
        heap.pop_back();
        sink(0);
        return ret;
    }
    void update(int key, ll value) {
        int pos = mp[key];
        val[key] = value;
        if (!swim(pos)) {
            sink(pos);
        }
    }
    int top() {
        return heap[0];
    }
    bool empty() {
        return heap.empty();
    }
};
vector<int> intersect[100'005];
vector<pair<int, int>> adj[100'005];
vector<ll> dist[100'005];
vector<int> idx[100'005], mp[100'005];
pair<int, int> rev[2'000'005];
int sparse[17][200'005];
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) {
    int n = x.size(), m = l.size();
    for (int i = 0; i < n; i++) {
        sparse[0][i] = h[i];
    }
    for (int j = 1; j < 17; j++) {
        for (int i = 0; i < n; i++) {
            sparse[j][i] = max(sparse[j - 1][i], sparse[j - 1][i + (1 << (j - 1))]);
        }
    }
    y.push_back(0);
    idx[s].push_back(m);
    dist[s].push_back(INF);
    for (int i = 0; i < m; i++) {
        int j = l[i];
        while (j <= r[i]) {
            if (y[i] <= h[j]) {
                intersect[i].push_back(j);
                j++;
                continue;
            }
            int mx = 0;
            for (int k = 16; k >= 0; k--) {
                if (y[i] > max(mx, sparse[k][j])) {
                    mx = max(mx, sparse[k][j]);
                    j += (1 << k);
                }
            }
            if (j <= r[i]) {
                intersect[i].push_back(j);
                j++;
            }
        }
        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});
            }
        }
    }
    int cur = 0;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < idx[i].size(); j++) {
            rev[cur] = {i, j};
            mp[i].push_back(cur++);
        }
    }
    bheap pq(cur);
    pq.push(mp[s][0], 0);
    dist[s][0] = 0;
    while (!pq.empty()) {
        int node = pq.pop();
        int i = rev[node].first;
        int j = rev[node].second;
        ll d = dist[i][j];
        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 (dist[nxt][nxth] == INF) {
                dist[nxt][nxth] = newd;
                pq.push(mp[nxt][nxth], newd);
            } else if (newd < dist[nxt][nxth]) {
                dist[nxt][nxth] = newd;
                pq.update(mp[nxt][nxth], newd);
            }
        }
    }
    ll ans = INF;
    for (int i = 0; i < dist[g].size(); i++) {
        ans = min(ans, dist[g][i] + y[idx[g][i]]);
    }
    // for (auto i : dist[g]) {
    //     ans = min(ans, i.first + i.second);
    // }
    if (ans >= INF) return -1;
    return ans;
}

Compilation message (stderr)

walk.cpp: In member function 'void bheap::sink(int)':
walk.cpp:14:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   14 |         while ((pos << 1) + 1 < heap.size()) {
      |                ~~~~~~~~~~~~~~~^~~~~~~~~~~~~
walk.cpp:17:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   17 |             if (r < heap.size() && val[heap[r]] < val[heap[l]]) smallest = r;
      |                 ~~^~~~~~~~~~~~~
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:110:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  110 |         for (int k = 0; k < intersect[i].size(); k++) {
      |                         ~~^~~~~~~~~~~~~~~~~~~~~
walk.cpp:114:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  114 |         for (int k = 0; k < intersect[i].size(); k++) {
      |                         ~~^~~~~~~~~~~~~~~~~~~~~
walk.cpp:115:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  115 |             if (k + 1 < intersect[i].size()) {
      |                 ~~~~~~^~~~~~~~~~~~~~~~~~~~~
walk.cpp:125:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  125 |         for (int j = 0; j < idx[i].size(); j++) {
      |                         ~~^~~~~~~~~~~~~~~
walk.cpp:151:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  151 |     for (int i = 0; i < dist[g].size(); i++) {
      |                     ~~^~~~~~~~~~~~~~~~

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