Submission #452680

#	Time	Username	Problem	Language	Result	Execution time	Memory
452680		naman1601	Valley (BOI19_valley)	C++17	100 / 100	334 ms	44740 KiB

valley

/*
++[---------->+<]>.-[------>+<]>-.++++++++.+++++.-[->+++++<]>-.-[--->++<]>--.+.[--->+<]>---.[->+++<]>++.++++++.-------.++++++.--[--->+<]>.-[->+++<]>-..+++++++++++++.[----->++<]>.------------.+[----->+<]>.--------.+++++++++++++.-------------.--[--->+<]>-.---[->++++<]>-.++++[->+++<]>.--[--->+<]>-.[->+++<]>++.-.+++.---.-[->+++<]>.-[--->++<]>+.++++.------.[--->+<]>---.+[----->+<]>.------------.+++++++.-------.--[--->+<]>---.+++[->+++<]>++..+++++++++.---------.-[->+++<]>.+[----->+<]>+.-------------.+++++++.+.----[->+++<]>-.
*/
#include <bits/stdc++.h>
using namespace std;

typedef long long big;
typedef long double ludo;
#define pbb pair<big, big>
#define pii pair<int, int>
#define fe first
#define se second
#define maxheap priority_queue
#define mset multiset
#define uset unordered_set
#define umap unordered_map
#define fr(i, s, e) for(int i = s; i < e; i++)
#define revfr(i, s, e) for(int i = s - 1; i >= e; i--)
#define getv(v, n) for(int i = 0; i < n; i++) cin >> v[i];
#define speed ios_base::sync_with_stdio(false); cin.tie(NULL)
#define nl "\n"
// #define debug(text) if(do_debug) {cout << (#text) << ": " << text << endl;}
#ifdef naman1601
#define debug(text) cout << (#text) << ": " << text << endl;
#else
#define debug(text)
#endif

const big mod = 1000000007;
// const big mod = 998244353;
const big infinity = 3000000000000000000;
const int inf = 1e9 + 5;
bool do_debug = false;


const int maxn = 1e5 + 5;
int n_nodes, nq, n_shops, destination;
vector<int> adj[maxn];
big attribute[maxn];
vector<array<int, 2>> edges;
map<int, int> ew[maxn];


struct lca {

	int n, tl;
	vector<int> t;
	vector<int> first;
	vector<int> euler;
	vector<int> dv;

	void init(int N) {

		n = N;
		euler.clear();
		euler.reserve(2 * n);
		first.clear();
		first.resize(n);
		dv.clear();
		dv.resize(n);

		dv[destination] = 0;
		dfs(destination, destination);

		tl = euler.size();
		t.clear();
		t.resize(tl << 2, -1);
		build(1, 0, tl - 1);
	}

	int get_lca(int u, int v) {

		int l = first[u], r = first[v];
		if(l > r) swap(l, r);
		return query(1, 0, tl - 1, l, r);
	}

	void dfs(int node, int parent) {

		first[node] = euler.size();
		euler.push_back(node);

		for(int next : adj[node]) {

			if(next == parent) continue;

			dv[next] = dv[node] + 1;
			dfs(next, node);
			euler.push_back(node);
		}
	}

	int task(int child1, int child2) {

		if(child1 == -1) return child2;
		if(child2 == -1) return child1;

		if(dv[child1] < dv[child2]) {

			return child1;

		} else {

			return child2;
		}
	}

	void build(int node, int l, int r) {
	
		if(l == r) {
	
			t[node] = euler[l];
	
		} else {
	
			int mid = (l + r) >> 1;
			build(node << 1, l, mid);
			build((node << 1) + 1, mid + 1, r);
			t[node] = task(t[node << 1], t[(node << 1) + 1]);
		}
	}

	int query(int node, int l, int r, int lq, int rq) {
	
		if(lq > rq) {
	
			return -1;
	
		} else if(lq <= l && rq >= r) {
	
			return t[node];
	
		} else {
	
			int mid = (l + r) >> 1;
			return task(query(node << 1, l, mid, lq, min(rq, mid)), query((node << 1) + 1, mid + 1, r, max(lq, mid + 1), rq));
		}
	}
};

lca L;


struct hld_t {

	int tl;
	vector<big> t;

	void init(int l, big val) {

		tl = l;
		t = vector<big>(tl << 2, val);
	}

	big task(big child1, big child2) {
	
		return min(child1, child2);
	}
	
	void update(int node, int l, int r, int pos, big val) {
	
		if(l == r) {
	
			t[node] = val;
	
		} else {
	
			int mid = (l + r) >> 1;
	
			if(pos <= mid) {
	
				update(node << 1, l, mid, pos, val);
	
			} else {
	
				update((node << 1) + 1, mid + 1, r, pos, val);
			}
	
			t[node] = task(t[node << 1], t[(node << 1) + 1]);
		}
	}

	void update(int pos, big val) {

		update(1, 0, tl - 1, pos, val);
	}
	
	big query(int node, int l, int r, int lq, int rq) {
	
		if(lq > rq) {
	
			return infinity;
	
		} else if(lq <= l && rq >= r) {
	
			return t[node];
	
		} else {
	
			int mid = (l + r) >> 1;
			return task(query(node << 1, l, mid, lq, min(rq, mid)), query((node << 1) + 1, mid + 1, r, max(lq, mid + 1), rq));
		}
	}

	big query(int lq, int rq) {

		return query(1, 0, tl - 1, lq, rq);
	}
	
	void build(vector<int>& v, int node, int l, int r) {
	
		if(l == r) {
	
			t[node] = attribute[v[l]];

			// replace attribute with appropriate variable
	
		} else {
	
			int mid = (l + r) >> 1;
			build(v, node << 1, l, mid);
			build(v, (node << 1) + 1, mid + 1, r);
			t[node] = task(t[node << 1], t[(node << 1) + 1]);
		}
	}

	void build(vector<int>& v) {

		build(v, 1, 0, tl - 1);
	}
};


struct hld {

	int n;
	vector<int> hld_path;
	vector<int> pos;
	vector<int> heavy_of;
	vector<int> head_of;
	vector<int> parent_of;

	hld_t t;

	void init(int N) {

		n = N;

		hld_path.clear();
		hld_path.reserve(n);
		pos.clear();
		pos.resize(n);
		heavy_of.clear();
		heavy_of.resize(n, -1);
		head_of.clear();
		head_of.resize(n);
		parent_of.clear();
		parent_of.resize(n);

		t.init(n, infinity);

		parent_of[destination] = destination;
		dfs(destination);
		head_of[destination] = destination;
		decompose(destination);

		t.build(hld_path);
	}

	int dfs(int node) {

		int subtree_size = 1;
		int current_heavy_size = -1;

		for(int next : adj[node]) {

			if(next == parent_of[node]) continue;

			parent_of[next] = node;
			int next_size = dfs(next);
			subtree_size += next_size;

			if(next_size > current_heavy_size) {

				current_heavy_size = next_size;
				heavy_of[node] = next;
			}
		}

		return subtree_size;
	}

	void decompose(int node) {

		pos[node] = hld_path.size();
		hld_path.push_back(node);

		if(heavy_of[node] != -1) {

			head_of[heavy_of[node]] = head_of[node];
			decompose(heavy_of[node]);
		}

		for(int next : adj[node]) {

			if(next == heavy_of[node] || next == parent_of[node]) continue;

			head_of[next] = next;
			decompose(next);
		}
	}

	big task(big v1, big v2) {

		return min(v1, v2);
	}

	big query(int node, int ancestor) {

		big retval = infinity;

		for(; head_of[node] != head_of[ancestor]; node = parent_of[head_of[node]]) {

			retval = task(retval, t.query(pos[head_of[node]], pos[node]));
		}

		retval = task(retval, t.query(pos[ancestor], pos[node]));
		return retval;
	}

	void update(int node, big value) {

		t.update(pos[node], value);
	}
};

hld h;


big dp[maxn], dep[maxn];
int start[maxn], fin[maxn];
vector<int> euler;


void init(int v, int p, big d) {

	dep[v] = d;

	for(int u : adj[v]) {

		if(u == p) continue;

		init(u, v, d + ew[u][v]);
	}
}

void dfs(int v, int p) {

	start[v] = euler.size();
	euler.push_back(v);

	for(int u : adj[v]) {

		if(u == p) continue;

		dfs(u, v);
		dp[v] = min(dp[v], ew[u][v] + dp[u]);
	}

	attribute[v] = dp[v] - dep[v];
	fin[v] = euler.size() - 1;
}


void solve() {

	cin >> n_nodes >> n_shops >> nq >> destination;
	destination--;

	fr(i, 0, n_nodes) dp[i] = infinity;
	edges.reserve(n_nodes - 1);

	fr(i, 0, n_nodes - 1)  {

		int u, v, w;
		cin >> u >> v >> w;
		u--; v--;

		ew[u][v] = w;
		ew[v][u] = w;
		adj[u].push_back(v);
		adj[v].push_back(u);
		edges.push_back({u, v});
	}

	init(destination, destination, 0);

	fr(i, 0, n_shops) {

		int v;
		cin >> v;
		v--;
		dp[v] = 0;
	}

	dfs(destination, destination);

	fr(i, 0, n_nodes - 1) {

		if(start[edges[i][0]] > start[edges[i][1]]) {

			swap(edges[i][0], edges[i][1]);
		}
	}


	// L.init(n_nodes);
	h.init(n_nodes);

	fr(i, 0, nq) {

		int e, v;
		cin >> e >> v;
		e--; v--;

		int u = edges[e][1];
		// cout << "i: " << u << nl;

		if(start[v] >= start[u] && start[v] <= fin[u]) {

			big r = dep[v] + h.query(v, u);

			if(r < infinity) {

				cout << r << nl;

			} else {

				cout << "oo\n";
			}

		} else {

			cout << "escaped\n";
		}
	}
}


int main() {
	
	speed;

	int q = 1;
	// cin >> q;

	while(q-- > 0) {

		solve();
	}

	return 0;
}

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