Submission #844066

#	Time	Username	Problem	Language	Result	Execution time	Memory
844066		Darren0724	Evacuation plan (IZhO18_plan)	C++17	100 / 100	1182 ms	78508 KiB

plan

#include <bits/stdc++.h>
using namespace std;
const int N = 100005;
const int INF = 1e9;
vector<pair<int, int>> adj[N];
struct info {
    int a, b, l, m, r, id;
};
bool operator<(info &a, info &b) {
    return make_pair(a.m, a.id) > make_pair(b.m, b.id);
}
struct DSU {
    vector<int> pa, sz;
    DSU(int n) {
        pa.resize(n);
        sz.resize(n, 1);
        iota(pa.begin(), pa.end(), 0);
    }
    int Find(int k) {
        if (k == pa[k]) {
            return k;
        }
        return pa[k] = Find(pa[k]);
    }
    void onion(int a, int b) {
        a = Find(a), b = Find(b);
        if (a == b) {
            return;
        }
        if (sz[a] > sz[b]) {
            swap(a, b);
        }
        pa[a] = b;
        sz[b] += sz[a];
    }
};
int32_t main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    int n, m;
    cin >> n >> m;
    for (int i = 0; i < m; i++) {
        int a, b, c;
        cin >> a >> b >> c;
        adj[a].push_back({b, c});
        adj[b].push_back({a, c});
    }
    vector<int> dis(N, INF);
    priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> pq;
    int shaoji;
    cin >> shaoji;
    for (int i = 0; i < shaoji; i++) {
        int k;
        cin >> k;
        dis[k] = 0;
        pq.push({0, k});
    }
    while (pq.size()) {
        int a, b;
        tie(a, b) = pq.top();
        pq.pop();
        if (a != dis[b]) {
            continue;
        }
        for (auto &e : adj[b]) {
            if (dis[e.first] > a + e.second) {
                dis[e.first] = a + e.second;
                pq.push({dis[e.first], e.first});
            }
        }
    }
    vector<info> v;
    for (int i = 1; i <= n; i++) {
        for (auto &e : adj[i]) {
            if (dis[i] <= dis[e.first]) {
                v.push_back({i, e.first, 0, dis[i], 0, INF});
            }
        }
    }
    int q;
    cin >> q;
    vector<int> ans(q);
    int solved = 0;
    for (int i = 0; i < q; i++) {
        int a, b;
        cin >> a >> b;
        int c = INF / 2;
        v.push_back({a, b, 0, c, INF, i});
    }
    sort(v.begin(), v.end());
    vector<info> v1;
    while (solved != q) {
        int sz = v.size();
        DSU d(n + 1);
        for (int i = 0; i < sz; i++) {
            // cout<<v[i].m<<' ';
            if (v[i].id == INF) {
                d.onion(v[i].a, v[i].b);
                v1.push_back(v[i]);
            } else {
                if (d.Find(v[i].a) == d.Find(v[i].b)) {
                    v[i].l = v[i].m;
                } else {
                    v[i].r = v[i].m;
                }
                if (v[i].r - v[i].l == 1) {
                    ans[v[i].id] = v[i].l;
                    solved++;
                } else {
                    v[i].m = (v[i].l + v[i].r) / 2;
                    v1.push_back(v[i]);
                }
            }
        }
        // cout<<endl;
        v = v1;
        v1.clear();
        sort(v.begin(), v.end());
    }
    for (int i = 0; i < q; i++) {
        cout << ans[i] << '\n';
    }

    return 0;
}
/*
9 12
1 9 4
1 2 5
2 3 7
2 4 3
4 3 6
3 6 4
8 7 10
6 7 5
5 8 1
9 5 7
5 4 12
6 8 2
2
4 7
5
1 6
5 3
4 8
5 8
1 5
*/

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