Submission #774646

#	Time	Username	Problem	Language	Result	Execution time	Memory
774646		horiiseun	Valley (BOI19_valley)	C++17	100 / 100	150 ms	41328 KiB

valley

#include <iostream>
#include <vector>
#include <tuple>
#include <queue>
#include <stack>
#include <deque>
#include <set>
#include <map>
#include <cmath>
#include <random>
#include <string>
#include <cassert>
#include <climits>
#include <algorithm>
#include <unordered_set>
#include <unordered_map>
using namespace std;

#define ll long long
#define f first
#define s second

void __print(int x) { cerr << x; }
void __print(long x) { cerr << x; }
void __print(long long x) { cerr << x; }
void __print(unsigned x) { cerr << x; }
void __print(unsigned long x) { cerr << x; }
void __print(unsigned long long x) { cerr << x; }
void __print(float x) { cerr << x; }
void __print(double x) { cerr << x; }
void __print(long double x) { cerr << x; }
void __print(char x) { cerr << '\'' << x << '\''; }
void __print(const char *x) { cerr << '\"' << x << '\"'; }
void __print(const string &x) { cerr << '\"' << x << '\"'; }
void __print(bool x) { cerr << (x ? "true" : "false"); }

template<typename A> void __print(const A &x);
template<typename A, typename B> void __print(const pair<A, B> &p);
template<typename... A> void __print(const tuple<A...> &t);
template<typename T> void __print(stack<T> s);
template<typename T> void __print(queue<T> q);
template<typename T, typename... U> void __print(priority_queue<T, U...> q);

template<typename A> void __print(const A &x) {
    bool first = true;
    cerr << '{';
    for (const auto &i : x) {
        cerr << (first ? "" : ","), __print(i);
        first = false;
    }
    cerr << '}';
}

template<typename A, typename B> void __print(const pair<A, B> &p) {
    cerr << '(';
    __print(p.f);
    cerr << ',';
    __print(p.s);
    cerr << ')';
}

template<typename... A> void __print(const tuple<A...> &t) {
    bool first = true;
    cerr << '(';
    apply([&first] (const auto &...args) { ((cerr << (first ? "" : ","), __print(args), first = false), ...); }, t);
    cerr << ')';
}

template<typename T> void __print(stack<T> s) {
    vector<T> debugVector;
    while (!s.empty()) {
        T t = s.top();
        debugVector.push_back(t);
        s.pop();
    }
    reverse(debugVector.begin(), debugVector.end());
    __print(debugVector);
}

template<typename T> void __print(queue<T> q) {
    vector<T> debugVector;
    while (!q.empty()) {
        T t = q.front();
        debugVector.push_back(t);
        q.pop();
    }
    __print(debugVector);
}

template<typename T, typename... U> void __print(priority_queue<T, U...> q) {
    vector<T> debugVector;
    while (!q.empty()) {
        T t = q.top();
        debugVector.push_back(t);
        q.pop();
    }
    __print(debugVector);
}

void _print() { cerr << "]\n"; }

template <typename Head, typename... Tail> void _print(const Head &H, const Tail &...T) {
    __print(H);
    if (sizeof...(T)) cerr << ", ";
    _print(T...);
}

#ifdef DEBUG
	#define D(...) cerr << "Line: " << __LINE__ << " [" << #__VA_ARGS__ << "] = ["; _print(__VA_ARGS__)
#else
	#define D(...)
#endif

int n, s, q, e, k, r, hgr, lwr, st, idx, in[100005], out[100005], depth[100005], par[100005][20];
ll dist[100005], val[100005][20], ans;
vector<pair<int, int>> edges, adj[100005];
bool shop[100005];

void dfs1(int curr, int p) {
	in[curr] = idx++;
	for (auto [i, d] : adj[curr]) {
		if (i == p) continue;
		depth[i] = depth[curr] + 1;
		dist[i] = dist[curr] + d;
		par[i][0] = curr;
		dfs1(i, curr);
	}
	out[curr] = idx++;
}

void dfs2(int curr, int p) {
	for (auto [i, d] : adj[curr]) {
		if (i == p) continue;
		dfs2(i, curr);
	}
	if (shop[curr]) val[curr][0] = dist[curr];
	else val[curr][0] = 1e18;
	for (auto [i, d] : adj[curr]) {
		val[curr][0] = min(val[curr][0], val[i][0]);
	}
}

int main() {

	ios_base::sync_with_stdio(false);
	cin.tie(0);

	cin >> n >> s >> q >> e;
	for (int i = 0, a, b, w; i < n - 1; i++) {
		cin >> a >> b >> w;
		adj[a].push_back({b, w});
		adj[b].push_back({a, w});
		edges.push_back({a, b});
	}
	for (int i = 0, x; i < s; i++) {
		cin >> x;
		shop[x] = true;
	}

	dfs1(e, -1);

	fill(&val[0][0], &val[0][0] + sizeof(val) / sizeof(val[0][0]), 1e18);
	dfs2(e, -1);
	for (int i = 1; i <= n; i++) {
		val[i][0] = val[i][0] - 2 * dist[i];
	}
	
	for (int i = 1; i < 20; i++) {
		for (int j = 1; j <= n; j++) {
			par[j][i] = par[par[j][i - 1]][i - 1];
			val[j][i] = min(val[j][i - 1], val[par[j][i - 1]][i - 1]);
		}
	}

	while (q--) {
		cin >> k >> r;
		hgr = edges[k - 1].f;
		lwr = edges[k - 1].s;
		if (depth[hgr] > depth[lwr]) swap(hgr, lwr);
		if (!(in[lwr] <= in[r] && out[r] <= out[lwr])) {
			cout << "escaped\n";
			continue;
		}
		ans = 1e18, st = r;
		for (int i = 19; i >= 0; i--) {
			if (depth[r] - depth[lwr] >= 1 << i) {
				ans = min(ans, val[r][i]);
				r = par[r][i];
			}
		}
		ans = min(ans, val[lwr][0]);
		if (ans >= 1e15) cout << "oo\n";
		else cout << dist[st] + ans << "\n";
	}

}

• Subtask 1: 9 / 9
• Subtask 2: 27 / 27
• Subtask 3: 23 / 23
• Subtask 4: 41 / 41