Submission #1098321

#	Time	Username	Problem	Language	Result	Execution time	Memory
1098321		vjudge1	Evacuation plan (IZhO18_plan)	C++17	100 / 100	436 ms	54732 KiB

plan

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pll pair<ll, ll>
#define fi first
#define se second
const ll N = 1e5+5;
ll n, m, q, k, s[N], p[N], dist[N], ans[N], lab[N];
vector<pll> adj[N];
set<ll> S[N];
void Dijkstra() {
    priority_queue<pll, vector<pll>, greater<pll>> pq;
    memset(dist, 0x3f, sizeof dist);
    for (int i= 1; i<= k; i++) {
        dist[s[i]] = 0;
        pq.push({0, s[i]});
    }
    while (!pq.empty()) {
        ll dis = pq.top().fi;
        ll u = pq.top().se;
        pq.pop();
        if (dis > dist[u]) continue;
        for (auto v : adj[u])
            if (dist[v.fi] > dist[u] + v.se) {
                dist[v.fi] = dist[u] + v.se;
                pq.push({dist[v.fi], v.fi});
            }
    }
}
ll find_set(ll u) {
    if (lab[u] < 0) return u;
    return lab[u] = find_set(lab[u]);
}
void union_set(ll u, ll v, ll w) {
    u = find_set(u);
    v = find_set(v);
    if (u == v) return;
    if (lab[u] > lab[v])
        swap(u, v);
    for (ll x : S[v]) {
        if (S[u].find(x) != S[u].end()) {
            ans[x] = w;
            S[u].erase(x);
        }
        else S[u].insert(x);
    }
    S[v].clear();
    lab[u] += lab[v];
    lab[v] = u;
}
signed main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    cin>>n>>m;
    for (int i= 1; i<= m; i++) {
        ll x, y, w;
        cin>>x>>y>>w;
        adj[x].push_back({y, w});
        adj[y].push_back({x, w});
    }
    cin>>k;
    for (int i= 1; i<= k; i++)
        cin>>s[i];
    cin>>q;
    for (int i= 1; i<= q; i++) {
        ll x, y;
        cin>>x>>y;
        S[x].insert(i);
        S[y].insert(i);
    }
    Dijkstra();
    for (int i= 1; i<= n; i++)
        p[i] = i;
    sort(p+1, p+n+1, [](ll x, ll y) {
        return dist[x] > dist[y];
    });
    memset(lab, -1, sizeof lab);
    for (int i= 1; i<= n; i++) {
        ll u = p[i];
        for (auto v : adj[u])
            if (dist[v.fi] >= dist[u])
                union_set(u, v.fi, dist[u]);
    }
    for (int i= 1; i<= q; i++)
        cout<<ans[i]<<'\n';
}

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