Submission #375730

#	Time	Username	Problem	Language	Result	Execution time	Memory
375730		ijxjdjd	Evacuation plan (IZhO18_plan)	C++14	100 / 100	739 ms	56916 KiB

plan

#include <bits/stdc++.h>
#define FR(i, N) for (int i = 0; i < int(N); i++)
#define all(x) begin(x), end(x)

using namespace std;

using ll = long long;

const int MAXN = (int)(1e5) + 5;
vector<pair<int, int>> adj[MAXN];
int closest[MAXN];


int par[MAXN];
int rk[MAXN];
int ans[MAXN];

unordered_set<int> keep[MAXN];
int find(int x) {
    if (par[x] == x) {
        return x;
    }
    else {
        return (par[x] = find(par[x]));
    }
}
void merge(int x, int y) {
    int px = find(x);
    int py = find(y);
    int res = min(closest[x], closest[y]);
    if (px != py) {
        if (rk[px] < rk[py]) {
            swap(px, py);
        }
        for (int e : keep[py]) {
            if (keep[px].count(e)) {
                keep[px].erase(e);
                ans[e] = res;
            }
            else {
                keep[px].insert(e);
            }
        }
        rk[px] += rk[py];
        par[py] = px;
    }
}
int main() {
	cin.tie(0);
	cin.sync_with_stdio(0);
	int N, M;
	cin >> N >> M;
	vector<pair<int, int>> edges(M);
	FR(i, N) {
        rk[i] = 1;
        par[i] = i;
	}
	FR(iter, M) {
        int a, b, w;
        cin >> a >> b >> w;
        a--, b--;
        adj[b].push_back({a, w});
        adj[a].push_back({b, w});
        edges[iter] = {a, b};
	}
	fill(all(closest), (int)(1e9));
	int K;
	cin >> K;
	priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> pq;
	FR(iter, K) {
        int a;
        cin >> a;
        a--;
        pq.push({0, a});
        closest[a]=0;
	}
	while (pq.size()) {
        auto nxt = pq.top();
        pq.pop();
        if (closest[nxt.second] == nxt.first) {
            for (auto& e : adj[nxt.second]) {
                if (closest[e.first] > closest[nxt.second] + e.second) {
                    closest[e.first] = closest[nxt.second] + e.second;
                    pq.push({closest[e.first], e.first});
                }
            }
        }
	}
	sort(all(edges), [] (const auto& lhs, auto& rhs) {
        return min(closest[lhs.first], closest[lhs.second]) > min(closest[rhs.first], closest[rhs.second]);
      });
    int Q;
    cin >> Q;
    FR(iter, Q){
        int u, v;
        cin >> u >> v;
        u--, v--;
        keep[u].insert(iter);
        keep[v].insert(iter);
    }
    for (auto& e : edges) {
        merge(e.first, e.second);
    }
    FR(i, Q) {
        cout << ans[i] << '\n';
    }
	return 0;
}

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