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Submission #604096

# Submission time Handle Problem Language Result Execution time Memory
604096 2022-07-24T17:54:54 Z l_reho Stranded Far From Home (BOI22_island) C++14
10 / 100
 362 ms 30924 KB 
#include<bits/stdc++.h>
using namespace std;

#define ll long long

struct info{
	int node;
	ll people;
	
	bool operator <(const info &i) const{
		return people > i.people;
	}
	
};

int N, M;

vector<ll> A;
vector<pair<ll, int>> A1;
vector<bool> taken, vis;
vector<vector<int>> graph;
vector<ll> P;

void dfs(int curr){
	vis[curr] = true;
	
	vector<int> adj = graph[curr];
	
	P[curr] = A[curr];
	
	for(int a : adj){
		if(vis[a]) continue;
		dfs(a);
		
		P[curr] += P[a];
		
	}
	
	
	// cout<<curr<<" "<<P[curr]<<endl;
}
/*

5 4
40 15 50 31 31
1 2
2 3
3 4
4 5
 
 
*/
void solver(int curr, int p, vector<int> &ans){
	vis[curr] = true;
	vector<int> adj = graph[curr];
	
	if((int)adj.size() == 1 && curr){
		if(P[curr] >= A[p]){
			ans[curr] = 1;
		}else{
			ans[curr] = 0;
		}
		return;
	}
	
	for(int a : adj){
		if(vis[a]) continue;
		
		if(curr){
			if(P[curr] >= A[p]){
				ans[curr] = 1;
			}else{
				ans[curr] = 0;
				continue;
			}
		}
		
		solver(a, curr, ans);
		
	}
	
}

void solve(){
	cin>>N>>M;
	
	A.assign(N, 0);
	A1.assign(N, pair<ll, int>());
	
	P.assign(N, 0);
	
	graph.assign(N, vector<int>());
	vis.assign(N, false);
	
	for(int i = 0; i < N; i++){
		int v;
		cin>>v;
		A[i] = v;
		A1[i] = {v, i};
	}
	
	sort(A1.begin(), A1.end(), greater<pair<ll, int>>());
	
	bool subtask3 = true;
	
	for(int i = 0; i < M; i++){
		int a, b;
		cin>>a>>b;
		a--;
		b--;
		graph[a].push_back(b);
		graph[b].push_back(a);
		
		subtask3 &= abs(a-b) == 1;
	}
	vector<int> ans(N, 2);
	
	
	ll sum = accumulate(A.begin(), A.end(), 0LL);
	
	bool subtask1 = (N <= 2000 && M <= 2000);
	
	if(subtask1){
		int last_color = N;
		
		for(int color = 0; color < last_color; color++){
			if(ans[color] != 2) continue;
			priority_queue<info> pq;
			// inizializzo la pq
			vector<int> adj = graph[color];
			
			taken.assign(N, false);
			taken[color] = true;
			
			for(int a : adj)
				pq.push({a, A[a]});
			
			ll total = A[color];
			stack<int> nodes;
			
			while(!pq.empty()){
				info i = pq.top();
				
				pq.pop();
				
				int node = i.node;
				ll abitants = i.people;
				
				if(taken[node]) continue;
				
				taken[node] = true;
				
				if(abitants > total)
					break;
				
				if(ans[node] == 1){
					total = sum;
					break;
				}
					
				nodes.push(node);
				total += abitants;
				vector<int> adj = graph[node];

				for(int a : adj){
					if(taken[a]) continue;
					pq.push({a, A[a]});
				}
				
			}
			// se ans[color] è false, allora saranno false anche tutti quelli
			// che sono stati convinti durante il processo e quindi è inutile
			// ricalcolarli
			ans[color] = total == sum;
			if(!ans[color]){
				while(!nodes.empty()){
					ans[nodes.top()] = 0;
					nodes.pop();
				}
			}
		}
		
		for(int i = 0; i < N; i++) cout<<ans[i];
		cout<<endl;
		return;
	}

	if(subtask3){
		vector<ll> pref_sum(N+1, 0);
		
		for(int i = 0; i < N; i++){
			pref_sum[i+1] += pref_sum[i] + A[i];
		}
		
		set<int> s;
		ans[A1[0].second] = 1;
		s.insert(A1[0].second);
		for(int i = 1; i < N; i++){
			int color = A1[i].second;
			// mi serve il primo abitante sulla sinistra già preso e 
			// il primo abitante sulla destra già preso cioè ans[i] = true;
			auto r = s.lower_bound(color);
			auto l = r;
			int r_idx = 0;
			int l_idx = 0;
			
			if(l == s.begin()){
				l_idx = -1;
			}else l_idx = *(--l);
			
			if(r == s.end()){
				r_idx = N;
			}else r_idx = *r;
			
			// cout<<"DEBUG-->"<<color<<" "<<l_idx<<" "<<r_idx<<endl;
			if(l_idx == -1)
				ans[color] = (pref_sum[r_idx] - pref_sum[l_idx+1]) >= A[r_idx];
			else if(r_idx == N)
				ans[color] = (pref_sum[r_idx] - pref_sum[l_idx+1]) >= A[l_idx];
			else ans[color] = (pref_sum[r_idx] - pref_sum[l_idx+1]) >= max(A[r_idx], A[l_idx]);
			
			if(ans[color])
				s.insert(color);
		}
		
		for(int i = 0; i < N; i++) cout<<ans[i];
		cout<<endl;
		return;
	}

	dfs(0);

	vis.assign(N, false);
	ans.assign(N, false);
	
	ans[0] = 1;
	
	solver(0, -1, ans);
	
	for(int i = 0; i < N; i++) cout<<ans[i];
	cout<<endl;
	
}

int main(){
	solve();
	return 0;
}

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 4 ms 476 KB Output is correct
5 Correct 4 ms 468 KB Output is correct
6 Correct 3 ms 468 KB Output is correct
7 Correct 5 ms 340 KB Output is correct
8 Correct 3 ms 340 KB Output is correct
9 Correct 3 ms 468 KB Output is correct
10 Correct 4 ms 488 KB Output is correct
11 Correct 3 ms 468 KB Output is correct
12 Correct 4 ms 468 KB Output is correct
13 Correct 2 ms 468 KB Output is correct
14 Correct 9 ms 492 KB Output is correct

Subtask #2
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 309 ms 30924 KB Output is correct
4 Correct 252 ms 28492 KB Output is correct
5 Correct 307 ms 18020 KB Output is correct
6 Correct 362 ms 18640 KB Output is correct
7 Correct 319 ms 18628 KB Output is correct
8 Correct 320 ms 18716 KB Output is correct
9 Correct 275 ms 18572 KB Output is correct
10 Correct 254 ms 20020 KB Output is correct
11 Correct 245 ms 20072 KB Output is correct
12 Correct 267 ms 18676 KB Output is correct
13 Correct 218 ms 20076 KB Output is correct
14 Correct 227 ms 21000 KB Output is correct
15 Incorrect 307 ms 29516 KB Output isn't correct
16 Halted 0 ms 0 KB -

Subtask #3
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Incorrect 355 ms 24244 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #4
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Incorrect 346 ms 20788 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #5
0 / 35.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 4 ms 476 KB Output is correct
5 Correct 4 ms 468 KB Output is correct
6 Correct 3 ms 468 KB Output is correct
7 Correct 5 ms 340 KB Output is correct
8 Correct 3 ms 340 KB Output is correct
9 Correct 3 ms 468 KB Output is correct
10 Correct 4 ms 488 KB Output is correct
11 Correct 3 ms 468 KB Output is correct
12 Correct 4 ms 468 KB Output is correct
13 Correct 2 ms 468 KB Output is correct
14 Correct 9 ms 492 KB Output is correct
15 Correct 0 ms 212 KB Output is correct
16 Correct 0 ms 212 KB Output is correct
17 Correct 309 ms 30924 KB Output is correct
18 Correct 252 ms 28492 KB Output is correct
19 Correct 307 ms 18020 KB Output is correct
20 Correct 362 ms 18640 KB Output is correct
21 Correct 319 ms 18628 KB Output is correct
22 Correct 320 ms 18716 KB Output is correct
23 Correct 275 ms 18572 KB Output is correct
24 Correct 254 ms 20020 KB Output is correct
25 Correct 245 ms 20072 KB Output is correct
26 Correct 267 ms 18676 KB Output is correct
27 Correct 218 ms 20076 KB Output is correct
28 Correct 227 ms 21000 KB Output is correct
29 Incorrect 307 ms 29516 KB Output isn't correct
30 Halted 0 ms 0 KB -