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Submission #477503

# Submission time Handle Problem Language Result Execution time Memory
477503 2021-10-02T10:35:14 Z Sohsoh84 Valley (BOI19_valley) C++17
100 / 100
 334 ms 83512 KB 
// ¯\_(ツ)_/¯
#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
typedef pair<ll, ll> pll;
 
#define all(x)                      (x).begin(),(x).end()
#define X                           first
#define Y                           second
#define sep                         ' '
#define endl                        '\n'
#define debug(x)                    cerr << #x << ": " <<  x << endl;
 
const ll MAXN = 1e6 + 10;
const ll INF = 1e18;
const ll MOD = 1e9 + 7; // 998244353; // 1e9 + 9;
const ll LOG = 20; 
 
int n, s, q, e, H[MAXN], tin[MAXN], tout[MAXN], T, par[MAXN][LOG];
vector<pair<int, int>> adj[MAXN];
vector<pair<int, int>> edges;
bool B[MAXN], sub_g[MAXN];
ll dist[MAXN], dp_up[MAXN], Down[MAXN][LOG], Up[MAXN][LOG];
pair<pll, pll> dp[MAXN]; 
 
void dfs(int v, int p) {
	par[v][0] = p;
	tin[v] = T++;
	H[v] = H[p] + 1;
	dp[v] = {{INF, 0}, {INF, 0}};
 
	if (v == e) sub_g[v] = true;
	if (B[v]) dp[v].X = {0, v};
	
	for (auto e : adj[v]) {
		int u = e.X, w = e.Y;
		if (u == p) continue;
 
		dist[u] = dist[v] + w;
		dfs(u, v);
		sub_g[v] |= sub_g[u];	
 
		if (dp[u].X.X + w < dp[v].X.X) {
			dp[v].Y = dp[v].X;
			dp[v].X = {dp[u].X.X + w, u};
		} else if (dp[u].X.X + w < dp[v].Y.X) dp[v].Y = {dp[u].X.X + w, u};
	}
 
	tout[v] = T++;
}
 
bool SubG(int v, int u) {
	return tin[v] <= tin[u] && tout[v] >= tout[u];
}
 
void dfs_up(int v, int p, int w) {
	dp_up[v] = min(INF, dp_up[p] + w);
	if (dp[p].X.Y != v) dp_up[v] = min(dp[p].X.X + w, dp_up[v]);
	if (dp[p].Y.Y != v) dp_up[v] = min(dp[p].Y.X + w, dp_up[v]);
	if (B[v]) dp_up[v] = 0;
 
	for (auto e : adj[v]) 
		if (e.X != p)
			dfs_up(e.X, v, e.Y);
}
 
ll Val(int v, int u) {
	if (dp[v].X.Y != u) return dp[v].X.X;
	else return dp[v].Y.X;
}
 
int Par(int v, int k) {
	for (int i = LOG - 1; i >= 0; i--) 
		if (k & (1 << i))
			v = par[v][i];
	return v;
}
 
int LCA(int v, int u) {
	if (H[v] < H[u]) swap(v, u);
	v = Par(v, H[v] - H[u]);
	if (v == u) return v;
 
	for (int i = LOG - 1; i >= 0; i--)
		if (par[v][i] != par[u][i])
			v = par[v][i], u = par[u][i];
	return par[v][0];
}
 
ll LD(int v, int k) {
	int R = v;
	if (k < 0) return INF;
	ll ans = dp[v].X.X;
 
	for (int i = LOG - 1; i >= 0; i--) {
		if (k & (1 << i)) {
			ans = min(ans, Down[v][i] + dist[R] - dist[v]);
			v = par[v][i];
		}
	}
 
	return ans;
}
 
ll UD(int v, int k) {
	if (k <= 0) return INF;	
	ll ans = INF;
 
	int R = Par(v, k);
	for (int i = LOG - 1; i >= 0; i--) {
		if (k & (1 << i)) {
			ans = min(ans, Up[v][i] + dist[par[v][i]] - dist[R]);
			v = par[v][i];
		}
	}
 
	return ans;
}
 
int main() {
	ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
	cin >> n >> s >> q >> e;
	for (int i = 0; i < n - 1; i++) {
		int u, v, w;
		cin >> u >> v >> w;
		adj[u].push_back({v, w});
		adj[v].push_back({u, w});
		edges.push_back({u, v});
	}
 
	for (int i = 0; i < s; i++) {
		int x;
		cin >> x;
		B[x] = true;
	}
	
	dp_up[0] = INF;
	dp[0] = {{INF, INF}, {INF, INF}};
 
	dfs(1, 0);
	dfs_up(1, 0, 0);
	
	for (int i = 0; i <= n; i++) Down[i][0] = min(dp[i].X.X, dp[par[i][0]].X.X + dist[i] - dist[par[i][0]]), Up[i][0] = Val(par[i][0], i);
 
	for (int i = 1; i < LOG; i++) {
		for (int v = 1; v <= n; v++) {
			int p = par[v][i - 1];
			par[v][i] = par[p][i - 1];
			Down[v][i] = min(Down[v][i - 1], Down[p][i - 1] + dist[v] - dist[p]);
			Up[v][i] = min(Up[p][i - 1], Up[v][i - 1] + dist[p] - dist[par[v][i]]);
		}
	}
	
	while (q--) {
		int r, v;
		cin >> r >> v;
		int e_v = edges[r - 1].X, e_u = edges[r - 1].Y;
		if (H[e_v] < H[e_u]) swap(e_v, e_u);
 
		if (SubG(e_v, v)) {
			if (sub_g[e_v]) {
				cout << "escaped" << endl;
				continue;
			}
			
			ll ans = min(INF, LD(v, H[v] - H[e_v]));
			if (ans >= INF) cout << "oo" << endl;
			else cout << ans << endl;
			continue;
		}
 
		if (!sub_g[e_v]) {
			cout << "escaped" << endl;
			continue;
		}
 
		int lca = LCA(e_u, v);
		ll ans = dp_up[lca] + dist[v] - dist[lca];
		ans = min(ans, UD(e_v, H[e_v] - H[lca]) + dist[v] - dist[lca]);
		ans = min(ans, LD(v, H[v] - H[lca] - 1));
 
		if (ans >= INF) cout << "oo" << endl;
		else cout << ans << endl;
	}
	return 0;
}

Subtask #1
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 23960 KB Output is correct
2 Correct 15 ms 23964 KB Output is correct
3 Correct 15 ms 24016 KB Output is correct
4 Correct 15 ms 24052 KB Output is correct

Subtask #2
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 23960 KB Output is correct
2 Correct 15 ms 23964 KB Output is correct
3 Correct 15 ms 24016 KB Output is correct
4 Correct 15 ms 24052 KB Output is correct
5 Correct 13 ms 24336 KB Output is correct
6 Correct 15 ms 24380 KB Output is correct
7 Correct 14 ms 24392 KB Output is correct
8 Correct 14 ms 24400 KB Output is correct
9 Correct 14 ms 24364 KB Output is correct
10 Correct 14 ms 24352 KB Output is correct
11 Correct 13 ms 24316 KB Output is correct
12 Correct 14 ms 24308 KB Output is correct
13 Correct 14 ms 24348 KB Output is correct
14 Correct 15 ms 24408 KB Output is correct

Subtask #3
23.0 / 23.0

# Verdict Execution time Memory Grader output
1 Correct 188 ms 78232 KB Output is correct
2 Correct 224 ms 77880 KB Output is correct
3 Correct 248 ms 77848 KB Output is correct
4 Correct 265 ms 79844 KB Output is correct
5 Correct 257 ms 79544 KB Output is correct
6 Correct 294 ms 83512 KB Output is correct

Subtask #4
41.0 / 41.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 23960 KB Output is correct
2 Correct 15 ms 23964 KB Output is correct
3 Correct 15 ms 24016 KB Output is correct
4 Correct 15 ms 24052 KB Output is correct
5 Correct 13 ms 24336 KB Output is correct
6 Correct 15 ms 24380 KB Output is correct
7 Correct 14 ms 24392 KB Output is correct
8 Correct 14 ms 24400 KB Output is correct
9 Correct 14 ms 24364 KB Output is correct
10 Correct 14 ms 24352 KB Output is correct
11 Correct 13 ms 24316 KB Output is correct
12 Correct 14 ms 24308 KB Output is correct
13 Correct 14 ms 24348 KB Output is correct
14 Correct 15 ms 24408 KB Output is correct
15 Correct 188 ms 78232 KB Output is correct
16 Correct 224 ms 77880 KB Output is correct
17 Correct 248 ms 77848 KB Output is correct
18 Correct 265 ms 79844 KB Output is correct
19 Correct 257 ms 79544 KB Output is correct
20 Correct 294 ms 83512 KB Output is correct
21 Correct 183 ms 77584 KB Output is correct
22 Correct 200 ms 77344 KB Output is correct
23 Correct 207 ms 77244 KB Output is correct
24 Correct 274 ms 78556 KB Output is correct
25 Correct 250 ms 82104 KB Output is correct
26 Correct 189 ms 77808 KB Output is correct
27 Correct 210 ms 77372 KB Output is correct
28 Correct 223 ms 77384 KB Output is correct
29 Correct 251 ms 79272 KB Output is correct
30 Correct 315 ms 81108 KB Output is correct
31 Correct 178 ms 77824 KB Output is correct
32 Correct 219 ms 77460 KB Output is correct
33 Correct 232 ms 77656 KB Output is correct
34 Correct 260 ms 78780 KB Output is correct
35 Correct 334 ms 81580 KB Output is correct
36 Correct 308 ms 79484 KB Output is correct