Submission #1045862

#	Time	Username	Problem	Language	Result	Execution time	Memory
1045862		vjudge1	Evacuation plan (IZhO18_plan)	C++17	100 / 100	454 ms	52464 KiB

plan

#include <bits/stdc++.h>
using namespace std;
#define int long long
typedef long long ll;
const int N = 100011;
set<ll> qr[N];
int n, m;
ll d[N], p[N], res[N];
vector<pair<int, int>> g[N];

void dijkstra() {
    int k;
    cin >> k;
    fill(d + 1, d + N, LLONG_MAX);
    set<pair<ll, int>> st;

    for (int i = 0; i < k; i++) {
        int x;
        cin >> x;
        d[x] = 0;
        st.insert({0, x});
    }

    while (!st.empty()) {
        int v = st.begin()->second;
        st.erase(st.begin());

        for (auto [to, w] : g[v]) {
            if (d[to] > d[v] + w) {
                st.erase({d[to], to});
                d[to] = d[v] + w;
                st.insert({d[to], to});
            }
        }
    }
}

int get(int v) {
    if (p[v] == v) return v;
    return p[v] = get(p[v]);
}

int cur = 0;
void merge(int v, int u) {
    v = get(v);
    u = get(u);
    if (v == u) return;

    p[u] = v;
    if (qr[v].size() < qr[u].size()) {
        qr[v].swap(qr[u]);
    }

    for (auto i : qr[u]) {
        if (qr[v].find(i) == qr[v].end()) {
            qr[v].insert(i);
        } else {
            res[i] = cur;
            qr[v].erase(i);
        }
    }
    qr[u].clear();
}

void process()
{
    cin >> n >> m;

    for (int i = 0; i < m; i++) {
        int x, y, w;
        cin >> x >> y >> w;
        g[x].emplace_back(y, w);
        g[y].emplace_back(x, w);
    }

    dijkstra();

    int q;
    cin >> q;
    for (int i = 1; i <= q; i++)
    {
        int s, t;
        cin >> s >> t;
        qr[s].insert(i);
        qr[t].insert(i);
    }

    vector<int> b(n);
    iota(b.begin(), b.end(), 1);
    sort(b.begin(), b.end(), [&](int x, int y) {
        return d[x] > d[y];
    });

    iota(p + 1, p + n + 1, 1);

    for (int i : b)
    {
        cur = d[i];
        for (auto [to, w] : g[i])
        {
            if (d[to] >= d[i]) {
                merge(i, to);
            }
        }
    }

    for (int i = 1; i <= q; i++)
    {
        cout << res[i] << '\n';
    }
}

main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);

    #define task "phcbaka"
    if (fopen(task ".inp", "r"))
    {
        freopen(task ".inp", "r", stdin);
        freopen(task ".out", "w", stdout);
    }

    process();
}

Compilation message (stderr)

plan.cpp:113:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
  113 | main()
      | ^~~~
plan.cpp: In function 'int main()':
plan.cpp:121:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  121 |         freopen(task ".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
plan.cpp:122:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  122 |         freopen(task ".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 13 / 13
• Subtask 3: 12 / 12
• Subtask 4: 19 / 19
• Subtask 5: 46 / 46