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Submission #244466

# Submission time Handle Problem Language Result Execution time Memory
244466 2020-07-04T06:36:27 Z oolimry Pipes (CEOI15_pipes) C++14
50 / 100
 1327 ms 21480 KB 
//HAPPY BIRTHDAY!!!
#include <bits/stdc++.h>
#define push_back emplace_back
using namespace std;
typedef pair<int,int> ii;

struct UFDS{
	int n;
	int p[100005];
	
	void init(int _n){
		n = _n;
		for(int i = 1;i <= n;i++) p[i] = i;
	}
	
	int find(int u){
		if(p[u] == u) return u;
		else{
			p[u] = find(p[u]);
			return p[u];
		}
	}
	
	void unionSet(int u, int P){
		u = find(u); P = find(P);
		if(u == P) return;
		p[u] = P;
	}
} tree, bridge;

vector<int> nodes[100005];
int p[100005];
int depth[100005];
vector<ii> possible;

void reroot(int u){
	vector<int> order;
	while(u != 0){
		order.push_back(u);
		u = p[u];
	}
	
	int sz = order.size(); order.push_back(0);
	for(int i = 0;i < sz;i++){
		p[order[i+1]] = order[i];
		depth[order[i]] = sz-i-1;
	}
	order.clear();
}

signed main(){
	ios_base::sync_with_stdio(false); cin.tie(0);
	
	int n, E; cin >> n >> E;
	
	tree.init(n+2); bridge.init(n+2);
	
	for(int i = 1;i <= n;i++) nodes[i].emplace_back(i);
	
	while(E--){
		int u, v; cin >> u >> v;
		if(bridge.find(u) == bridge.find(v)) continue;
		
		if(tree.find(u) == tree.find(v)){ ///bridge formed
			
			vector<int> path;
			
			while(u != v){
				if(depth[u] > depth[v]) swap(u,v); ///v is deeper now
				
				path.push_back(v);
				v = p[v];
			}
			
			int P = u;
			//cout << P << "\n";
			for(int x : path){
				p[x] = P;
				depth[x] = depth[P]+1;
				bridge.unionSet(x, P);
			}
		}
		else{ ///connect two trees to 1 tree
			int U = tree.find(u), V = tree.find(v);
			
			if(nodes[U].size() > nodes[V].size()){
				swap(U,V);
				swap(u,v);
			}
			
			tree.unionSet(U, V);
			reroot(u);
			p[u] = v;
			while(!nodes[U].empty()){
				int B = nodes[U].back();
				depth[B] += depth[v] + 1;
				nodes[V].emplace_back(B);
				nodes[U].pop_back();
			}
			
			//cout << u << " " << v << ":\n";
			//for(int i = 1;i <= n;i++) cout << p[i] << " ";
			//cout << "\n";
			//for(int i = 1;i <= n;i++) cout << depth[i] << " ";
			//cout << "\n";
			possible.push_back(u,v);
		}
	}
	
	for(ii e : possible){
		
		if(bridge.find(e.first) != bridge.find(e.second)){
			cout << e.first << " " << e.second << "\n";
		}
	}
}

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 2688 KB Output is correct
2 Correct 6 ms 2688 KB Output is correct

Subtask #2
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 10 ms 3072 KB Output is correct
2 Incorrect 10 ms 3072 KB Wrong number of edges

Subtask #3
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 111 ms 2944 KB Output is correct
2 Incorrect 101 ms 2944 KB Wrong number of edges

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 169 ms 3440 KB Output is correct
2 Correct 196 ms 3456 KB Output is correct

Subtask #5
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 307 ms 4352 KB Output is correct
2 Runtime error 281 ms 18548 KB Memory limit exceeded (if you are sure your verdict is not MLE, please contact us)

Subtask #6
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 413 ms 7792 KB Output is correct
2 Incorrect 374 ms 8684 KB Wrong number of edges

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 666 ms 8336 KB Output is correct
2 Correct 646 ms 9348 KB Output is correct

Subtask #8
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 878 ms 14976 KB Output is correct
2 Correct 816 ms 11408 KB Output is correct

Subtask #9
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1069 ms 9944 KB Output is correct
2 Correct 1020 ms 11628 KB Output is correct

Subtask #10
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1327 ms 9988 KB Output is correct
2 Runtime error 1256 ms 21480 KB Memory limit exceeded (if you are sure your verdict is not MLE, please contact us)