Submission #565748

#TimeUsernameProblemLanguageResultExecution timeMemory
565748RealSnakeEvacuation plan (IZhO18_plan)C++14
10 / 100
4077 ms468 KiB
#include "bits/stdc++.h"
using namespace std;

#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;

#define ll long long
#define mod 1000000007

ofstream fout(".out");
ifstream fin(".in");

vector<pair<int, int>> v[1001];
int d[1001], g[1001];
bool vis[1001];
int n, m, s, t, o, mn;

void dijkstra(int y) {
    for(int i = 1; i <= n; i++)
        g[i] = 1e9;
    set<pair<int, int>> s;
    s.insert({0, y});
    while(s.size()) {
        pair<int, int> p = *s.begin();
        s.erase(s.begin());
        int x = p.second;
        int cost = p.first;
        if(d[x] == 0) {
            d[y] = cost;
            return;
        }
        if(cost > g[x])
            continue;
        g[x] = cost;
        for(auto i : v[x]) {
            if(cost + i.second < g[i.first]) {
                g[i.first] = cost + i.second;
                s.insert({cost + i.second, i.first});
            }
        }
    }
}

pair<int, int> dfs(int x) {
    if(x == t)
        return {d[x], 1};
    if(g[x])
        return {g[x], 1};
    vis[x] = 1;
    int mx = 0, o = 0;
    for(auto i : v[x]) {
        if(d[i.first] && !vis[i.first]) {
            pair<int, int> p = dfs(i.first);
            if(p.second) {
                mx = max(mx, p.first);
                o = 1;
            }
        }
    }
    vis[x] = 0;
    if(o)
        g[x] = min(d[x], mx);
    return {min(d[x], mx), o};
}

signed main() {

    ios::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);

    cin >> n >> m;
    for(int i = 1; i <= n; i++)
        d[i] = 1e9;
    for(int i = 0; i < m; i++) {
        int a, b, c;
        cin >> a >> b >> c;
        v[a].push_back({b, c});
        v[b].push_back({a, c});
    }
    int k;
    cin >> k;
    for(int i = 0; i < k; i++) {
        int x;
        cin >> x;
        d[x] = 0;
    }
    for(int i = 1; i <= n; i++)
        dijkstra(i);
    int q;
    cin >> q;
    while(q--) {
        cin >> s >> t;
        bool b = 0;
        for(auto i : v[s]) {
            if(i.first == t) {
                b = 1;
                break;
            }
        }
        if(b) {
            cout << min(d[s], d[t]) << "\n";
            continue;
        }
        mn = 1e9;
        for(int i = 1; i <= n; i++)
            g[i] = 0;
        cout << dfs(s).first << "\n";
    }

    return 0;
}
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