oj.uz

Submission #497063

# Submission time Handle Problem Language Result Execution time Memory
497063 2021-12-22T09:26:00 Z _Avocado_ Valley (BOI19_valley) C++14
100 / 100
 473 ms 77896 KB 
#include <bits/stdc++.h>
#define int int64_t
using namespace std;

vector<vector<pair<int, int>>>graph;
vector<vector<int>>up, val;
vector<int>tin, tout, dist, lvl, shh, shop;

int timer = 0;
int l = 32;

int min(int a, int b){
	if(a < b) return a;
	return b;
}

void dfs(int v, int p){
	tin[v] = timer++;
	up[v][0] = p;

	if(shop[v]) shh[v] = 0;
	
	for(int i = 1; i<=l; ++i){
		up[v][i] = up[up[v][i-1]][i-1];
	}
	
	for(auto [u, w]: graph[v]){
		if(u != p){
			lvl[u] = lvl[v] + 1;
			dist[u] = dist[v] + w;
			dfs(u, v);
			shh[v] = min(shh[u] + w, shh[v]);
		} 			
	}
	
	tout[v] = timer++;
}

void table(int v, int p){
	val[v][0] = dist[v] - dist[p] + shh[p];
	
	for(int i = 1; i<=l; ++i){
		val[v][i] = min(val[v][i-1], val[up[v][i-1]][i-1] + dist[v] - dist[up[v][i-1]]);
		assert(dist[v] >= dist[up[v][i-1]]);
	}
	
	for(auto [u, w]: graph[v]) if(u != p) table(u, v);
	
}

int check(int u, int v){
	if(tin[u] <= tin[v] && tout[u] >= tout[v]) return 1;
	return 0;
}

int lca(int u, int v){
	if(check(u, v)) return u;
	if(check(v, u)) return v;
	
	for(int i = l; i>=0; --i){
		if(!check(up[u][i], v)) u = up[u][i];
	}
	
	return up[u][0];
}

signed main(){
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	
	int n, s, q, e; cin>>n>>s>>q>>e;
	--e;
	
	vector<pair<int, int>>edges;
	
	graph.assign(n, vector<pair<int, int>>());
	up.assign(n, vector<int>(33));
	val.assign(n, vector<int>(33));
	tin.assign(n, 0);
	tout.assign(n, 0);
	dist.assign(n, 0);
	lvl.assign(n, 0);
	shh.assign(n, 1e18);
	shop.assign(n, 0);
	
	for(int i = 0; i<n-1; ++i){
		int a, b, c; cin>>a>>b>>c;
		--a; --b;
		graph[a].push_back({b, c});
		graph[b].push_back({a, c});
		edges.push_back({a, b});
	}
	
	for(int i = 0; i<s; ++i){
		int c; cin>>c;
		--c;
		shop[c] = 1;
	}
	
	dfs(e, e);
	
	//for(auto u: shh) cout<<u<<" ";
	//cout<<endl;
	
	
	table(e, e);
	/*
	for(int i = 0; i<n; ++i){
		for(int j = 0; j<3; ++j) cout<<val[i][j]<<" ";
		cout<<endl;
	}
	cout<<endl;
	*/
	/*
	for(auto [x, y]: edges) cout<<x<<" "<<y<<endl;
	cout<<endl;
	*/
	/*
	for(int i = 0; i<n; ++i){
		for(int j = 0; j<5; ++j) cout<<val[i][j]<<" ";
		cout<<endl;
	}
	
	cout<<endl;
	
	for(auto u: dist) cout<<u<<" ";
	cout<<endl;
	*/
	
	
	
	for(int i = 0; i<q; ++i){
		int j, r; cin>>j>>r;
		--j; --r;
		int a = edges[j].first;
		int b = edges[j].second;
		int cur;
		
		if(lvl[a] > lvl[b]) cur = a;
		else cur = b;
		
		//cout<<cur<<" "<<r<<" "<<j<<endl;
		
		if(lca(cur, r) != cur) cout<<"escaped"<<'\n';
		else{
			
			int one = shh[r];
			int range = lvl[r] - lvl[cur];
			int jump = r;
			int two = 1e18;
			
			for(int i = l; i>=0; --i){
				if(range >= 1ll<<i){
					range -= 1ll<<i;
					two = min(two, val[jump][i] + dist[r] - dist[jump]);
					assert(dist[r] >= dist[jump]); 
					jump = up[jump][i];
					
					//cout<<jump<<" "<<two<<endl;

				}
			}
			
			if(min(one, two) < 1e18) cout<<min(one, two)<<'\n';
			else cout<<"oo"<<'\n';
			
			
		}
	}
	
	
	

	
	
	
	cout<<'\n';
}

Compilation message

valley.cpp: In function 'void dfs(int64_t, int64_t)':
valley.cpp:27:11: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   27 |  for(auto [u, w]: graph[v]){
      |           ^
valley.cpp: In function 'void table(int64_t, int64_t)':
valley.cpp:47:11: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   47 |  for(auto [u, w]: graph[v]) if(u != p) table(u, v);
      |           ^

Subtask #1
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 332 KB Output is correct
2 Correct 2 ms 460 KB Output is correct
3 Correct 2 ms 460 KB Output is correct
4 Correct 3 ms 332 KB Output is correct

Subtask #2
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 332 KB Output is correct
2 Correct 2 ms 460 KB Output is correct
3 Correct 2 ms 460 KB Output is correct
4 Correct 3 ms 332 KB Output is correct
5 Correct 2 ms 972 KB Output is correct
6 Correct 2 ms 972 KB Output is correct
7 Correct 2 ms 972 KB Output is correct
8 Correct 3 ms 972 KB Output is correct
9 Correct 2 ms 972 KB Output is correct
10 Correct 2 ms 972 KB Output is correct
11 Correct 2 ms 972 KB Output is correct
12 Correct 3 ms 972 KB Output is correct
13 Correct 2 ms 972 KB Output is correct
14 Correct 2 ms 972 KB Output is correct

Subtask #3
23.0 / 23.0

# Verdict Execution time Memory Grader output
1 Correct 228 ms 72652 KB Output is correct
2 Correct 276 ms 72452 KB Output is correct
3 Correct 290 ms 72724 KB Output is correct
4 Correct 364 ms 74524 KB Output is correct
5 Correct 340 ms 74696 KB Output is correct
6 Correct 462 ms 76836 KB Output is correct

Subtask #4
41.0 / 41.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 332 KB Output is correct
2 Correct 2 ms 460 KB Output is correct
3 Correct 2 ms 460 KB Output is correct
4 Correct 3 ms 332 KB Output is correct
5 Correct 2 ms 972 KB Output is correct
6 Correct 2 ms 972 KB Output is correct
7 Correct 2 ms 972 KB Output is correct
8 Correct 3 ms 972 KB Output is correct
9 Correct 2 ms 972 KB Output is correct
10 Correct 2 ms 972 KB Output is correct
11 Correct 2 ms 972 KB Output is correct
12 Correct 3 ms 972 KB Output is correct
13 Correct 2 ms 972 KB Output is correct
14 Correct 2 ms 972 KB Output is correct
15 Correct 228 ms 72652 KB Output is correct
16 Correct 276 ms 72452 KB Output is correct
17 Correct 290 ms 72724 KB Output is correct
18 Correct 364 ms 74524 KB Output is correct
19 Correct 340 ms 74696 KB Output is correct
20 Correct 462 ms 76836 KB Output is correct
21 Correct 265 ms 72624 KB Output is correct
22 Correct 253 ms 72628 KB Output is correct
23 Correct 283 ms 72756 KB Output is correct
24 Correct 372 ms 74812 KB Output is correct
25 Correct 473 ms 77896 KB Output is correct
26 Correct 257 ms 72752 KB Output is correct
27 Correct 264 ms 72460 KB Output is correct
28 Correct 273 ms 72732 KB Output is correct
29 Correct 366 ms 74188 KB Output is correct
30 Correct 427 ms 75868 KB Output is correct
31 Correct 232 ms 72752 KB Output is correct
32 Correct 266 ms 72652 KB Output is correct
33 Correct 284 ms 72756 KB Output is correct
34 Correct 366 ms 74700 KB Output is correct
35 Correct 426 ms 77572 KB Output is correct
36 Correct 345 ms 75136 KB Output is correct