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Submission #604088

# Submission time Handle Problem Language Result Execution time Memory
604088 2022-07-24T17:42:07 Z l_reho Stranded Far From Home (BOI22_island) C++14
10 / 100
 352 ms 30980 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 30 20
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, 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;
		
		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;
			
			ans[color] = (pref_sum[r_idx] - pref_sum[l_idx+1]) >= A1[i-1].first;
			
			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 224 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 5 ms 468 KB Output is correct
5 Correct 4 ms 468 KB Output is correct
6 Correct 3 ms 468 KB Output is correct
7 Correct 6 ms 472 KB Output is correct
8 Correct 5 ms 452 KB Output is correct
9 Correct 2 ms 468 KB Output is correct
10 Correct 4 ms 404 KB Output is correct
11 Correct 3 ms 468 KB Output is correct
12 Correct 5 ms 468 KB Output is correct
13 Correct 3 ms 468 KB Output is correct
14 Correct 10 ms 488 KB Output is correct

Subtask #2
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 308 ms 30980 KB Output is correct
4 Correct 298 ms 28496 KB Output is correct
5 Correct 309 ms 18020 KB Output is correct
6 Correct 331 ms 18568 KB Output is correct
7 Correct 334 ms 18700 KB Output is correct
8 Correct 327 ms 18704 KB Output is correct
9 Correct 337 ms 18484 KB Output is correct
10 Correct 247 ms 20024 KB Output is correct
11 Correct 287 ms 20076 KB Output is correct
12 Correct 273 ms 18652 KB Output is correct
13 Incorrect 272 ms 29416 KB Output isn't correct
14 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 352 ms 26204 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 20808 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 224 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 5 ms 468 KB Output is correct
5 Correct 4 ms 468 KB Output is correct
6 Correct 3 ms 468 KB Output is correct
7 Correct 6 ms 472 KB Output is correct
8 Correct 5 ms 452 KB Output is correct
9 Correct 2 ms 468 KB Output is correct
10 Correct 4 ms 404 KB Output is correct
11 Correct 3 ms 468 KB Output is correct
12 Correct 5 ms 468 KB Output is correct
13 Correct 3 ms 468 KB Output is correct
14 Correct 10 ms 488 KB Output is correct
15 Correct 1 ms 212 KB Output is correct
16 Correct 1 ms 212 KB Output is correct
17 Correct 308 ms 30980 KB Output is correct
18 Correct 298 ms 28496 KB Output is correct
19 Correct 309 ms 18020 KB Output is correct
20 Correct 331 ms 18568 KB Output is correct
21 Correct 334 ms 18700 KB Output is correct
22 Correct 327 ms 18704 KB Output is correct
23 Correct 337 ms 18484 KB Output is correct
24 Correct 247 ms 20024 KB Output is correct
25 Correct 287 ms 20076 KB Output is correct
26 Correct 273 ms 18652 KB Output is correct
27 Incorrect 272 ms 29416 KB Output isn't correct
28 Halted 0 ms 0 KB -