Submission #878152

#	Time	Username	Problem	Language	Result	Execution time	Memory
878152		The_Samurai	Evacuation plan (IZhO18_plan)	C++17	54 / 100	4051 ms	28124 KiB

plan

#include "bits/stdc++.h"
using namespace std;
using ll = long long;
const int inf = 1e9;

void solve() {
    int n, m, k, q;
    cin >> n >> m;
    vector<vector<pair<int, int>>> g(n + 1);
    for (int i = 0; i < m; i++) {
        int u, v, w;
        cin >> u >> v >> w;
        g[u].emplace_back(v, w);
        g[v].emplace_back(u, w);
    }
    cin >> k;
    vector<int> dist(n + 1, inf), roots(k);
    priority_queue<pair<int, int>> pq;
    for (int i = 0; i < k; i++) {
        int root;
        cin >> root;
        pq.emplace(0, root);
        dist[root] = 0;
    }
    vector<bool> vis(n + 1);
    while (!pq.empty()) {
        auto [d, u] = pq.top(); pq.pop();
        d = -d;
        if (vis[u]) continue;
        vis[u] = true;
        for (auto [v, w]: g[u]) {
            if (dist[v] <= d + w) continue;
            dist[v] = d + w;
            pq.emplace(-dist[v], v);
        }
    }
    for (int i = 1; i <= n; i++) sort(g[i].begin(), g[i].end());
    cin >> q;
    while (q--) {
        int s, t;
        cin >> s >> t;

        int i = lower_bound(g[s].begin(), g[s].end(), make_pair(t, 0)) - g[s].begin();
        if (i < g[s].size() and g[s][i].first == t) {
            cout << min(dist[s], dist[t]) << '\n';
            continue;
        }

        vector<int> ans(n + 1);
        vector<bool> vis(n + 1);
        ans[s] = dist[s];
        priority_queue<pair<int, int>> pq; pq.emplace(ans[s], s);
        while (!pq.empty()) {
            auto [d, u] = pq.top(); pq.pop();
            if (vis[u]) continue;
            vis[u] = true;
            for (auto [v, w]: g[u]) {
                if (ans[v] > min(ans[u], dist[v])) continue;
                ans[v] = min(ans[u], dist[v]);
                pq.emplace(ans[v], v);
            }
        }
        cout << ans[t] << '\n';
    }
}

int main() {
    cin.tie(0)->sync_with_stdio(false);
#ifdef sunnatov
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif

    int queries = 1;
//    cin >> queries;

    for (int test_case = 1; test_case <= queries; test_case++) {
#ifdef sunnatov
        cout << "Test case: " << test_case << endl;
#endif
        solve();
        cout << '\n';
    }
}

Compilation message (stderr)

plan.cpp: In function 'void solve()':
plan.cpp:44:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   44 |         if (i < g[s].size() and g[s][i].first == t) {
      |             ~~^~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 13 / 13
• Subtask 3: 12 / 12
• Subtask 4: 19 / 19
• Subtask 5: 0 / 46