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Submission #567475

# Submission time Handle Problem Language Result Execution time Memory
567475 2022-05-23T14:50:11 Z _karan_gandhi Valley (BOI19_valley) C++17
100 / 100
 277 ms 56156 KB 
#include <bits/stdc++.h>
using namespace std;

#define all(v) v.begin(), v.end()
#define endl '\n'
#define pl(var) " [" << #var << ": " << (var) << "] "
#define ll long long

template<typename A, typename B> ostream& operator<<(ostream &cout, pair<A, B> const &p) { return cout << "[" << p.first << ", " << p.second << "]"; }
template<typename A> ostream& operator<<(ostream &cout, vector<A> const &v) { cout << "["; for(int i = 0; i < (int)v.size(); i++) {if (i) cout << ", "; cout << v[i];} return cout << "]";}
template<typename A, typename B> istream& operator>>(istream& cin, pair<A, B> &p) { cin >> p.first; return cin >> p.second; }

vector<vector<pair<int, int>>> adj;
vector<int> tin, tout, par, dep;
vector<ll int> dist, dp1;
vector<bool> shop;
int timer = 0;

void dfs(int u, int p, ll int dis, int d = 0) {
	dist[u] = dis;
	tin[u] = timer++;
	par[u] = p;
	dep[u] = d;

	for (auto [v, w] : adj[u]) {
		if (v == p) continue;

		dfs(v, u, dis + w, d + 1);
	}

	if (shop[u]) dp1[u] = dist[u];
	else dp1[u] = 1e18;

	for (auto [v, wt] : adj[u]) {
		if (v == p) continue;

		dp1[u] = min(dp1[u], dp1[v]);
	}

	tout[u] = timer - 1;
}

bool is_acc(int acc, int child) {
	if (acc == child) return 1;
	return tin[acc] < tin[child] && tin[child] <= tout[acc];
}

void solve() {
	int n, s, q, e; cin >> n >> s >> q >> e;

	adj.resize(n);
	dp1.resize(n);
	tin.resize(n);
	tout.resize(n);
	dist.resize(n);
	shop.resize(n);
	par.resize(n);
	dep.resize(n);

	fill(all(dp1), 1e18);

	vector<pair<pair<int, int>, int>> edges;

	for (int i = 0; i < n - 1; i++) {
		int a, b; cin >> a >> b;
		int c; cin >> c;
		a--, b--;

		adj[a].emplace_back(b, c);
		adj[b].emplace_back(a, c);
		edges.emplace_back(make_pair(a, b), c);
	}

	for (int i = 0; i < s; i++) {
		int a; cin >> a;
		shop[a - 1] = 1;
	}

	// e is the root
	dfs(e - 1, e - 1, 0);
	for (int i = 0; i < n; i++) {
		dp1[i] = dp1[i] - 2 * dist[i];
	}

	const int LOG = 20;
	vector<vector<ll int>> jumpNode(n, vector<ll int>(20)), jumpDP(n, vector<ll int>(20));

	for (int i = 0; i < n; i++) {
		jumpNode[i][0] = par[i];
		jumpDP[i][0] = dp1[i];
	}

	for (int i = 1; i < LOG; i++) {
		for (int j = 0; j < n; j++) {
			jumpNode[j][i] = jumpNode[jumpNode[j][i - 1]][i - 1];
			jumpDP[j][i] = min(jumpDP[j][i - 1], jumpDP[jumpNode[j][i - 1]][i - 1]); // somewhat like sparse tables
		}
	}

	auto query = [&](int u, int k) -> ll int {
		int pow = LOG;
		ll int res = 1e18;

		while (k > 0) {
			while (k < (1 << pow)) pow--;
			res = min(res, jumpDP[u][pow]);
			u = jumpNode[u][pow];
			k -= (1 << pow);
		}

		return res;
	};

	while (q--) {
		int a, b; cin >> a >> b;

		a--, b--;
		pair<int, int> edge = edges[a].first;
		if (is_acc(edge.first, b) && is_acc(edge.second, b)) {
			int one = edge.first;
			if (dist[one] < dist[edge.second]) {
				one = edge.second;
			}

			ll int res = query(b, dep[b] - dep[one] + 1);
			if (res >= 1e16) {
				cout << "oo" << endl;
			} else {
				cout << res + dist[b] << endl;
			}
		} else {
			cout << "escaped" << endl;
		}
	}
}

int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);

	int T = 1;
	// cin >> T;
	while (T--)
		solve();
}

Subtask #1
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 340 KB Output is correct
2 Correct 3 ms 340 KB Output is correct
3 Correct 3 ms 340 KB Output is correct
4 Correct 4 ms 340 KB Output is correct

Subtask #2
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 340 KB Output is correct
2 Correct 3 ms 340 KB Output is correct
3 Correct 3 ms 340 KB Output is correct
4 Correct 4 ms 340 KB Output is correct
5 Correct 1 ms 724 KB Output is correct
6 Correct 1 ms 724 KB Output is correct
7 Correct 1 ms 724 KB Output is correct
8 Correct 1 ms 724 KB Output is correct
9 Correct 2 ms 724 KB Output is correct
10 Correct 2 ms 724 KB Output is correct
11 Correct 2 ms 724 KB Output is correct
12 Correct 3 ms 724 KB Output is correct
13 Correct 2 ms 724 KB Output is correct
14 Correct 2 ms 852 KB Output is correct

Subtask #3
23.0 / 23.0

# Verdict Execution time Memory Grader output
1 Correct 201 ms 50608 KB Output is correct
2 Correct 191 ms 50284 KB Output is correct
3 Correct 197 ms 50240 KB Output is correct
4 Correct 225 ms 52516 KB Output is correct
5 Correct 218 ms 52548 KB Output is correct
6 Correct 277 ms 54816 KB Output is correct

Subtask #4
41.0 / 41.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 340 KB Output is correct
2 Correct 3 ms 340 KB Output is correct
3 Correct 3 ms 340 KB Output is correct
4 Correct 4 ms 340 KB Output is correct
5 Correct 1 ms 724 KB Output is correct
6 Correct 1 ms 724 KB Output is correct
7 Correct 1 ms 724 KB Output is correct
8 Correct 1 ms 724 KB Output is correct
9 Correct 2 ms 724 KB Output is correct
10 Correct 2 ms 724 KB Output is correct
11 Correct 2 ms 724 KB Output is correct
12 Correct 3 ms 724 KB Output is correct
13 Correct 2 ms 724 KB Output is correct
14 Correct 2 ms 852 KB Output is correct
15 Correct 201 ms 50608 KB Output is correct
16 Correct 191 ms 50284 KB Output is correct
17 Correct 197 ms 50240 KB Output is correct
18 Correct 225 ms 52516 KB Output is correct
19 Correct 218 ms 52548 KB Output is correct
20 Correct 277 ms 54816 KB Output is correct
21 Correct 189 ms 50672 KB Output is correct
22 Correct 192 ms 50432 KB Output is correct
23 Correct 226 ms 50264 KB Output is correct
24 Correct 251 ms 52776 KB Output is correct
25 Correct 263 ms 56156 KB Output is correct
26 Correct 183 ms 50728 KB Output is correct
27 Correct 191 ms 50352 KB Output is correct
28 Correct 194 ms 50404 KB Output is correct
29 Correct 243 ms 52016 KB Output is correct
30 Correct 242 ms 53648 KB Output is correct
31 Correct 171 ms 50812 KB Output is correct
32 Correct 183 ms 50448 KB Output is correct
33 Correct 185 ms 50388 KB Output is correct
34 Correct 252 ms 52560 KB Output is correct
35 Correct 234 ms 55908 KB Output is correct
36 Correct 215 ms 53256 KB Output is correct