oj.uz

Submission #731656

# Submission time Handle Problem Language Result Execution time Memory
731656 2023-04-27T17:58:30 Z esomer Pipes (CEOI15_pipes) C++17
90 / 100
 5000 ms 8536 KB 
#include<bits/stdc++.h>
 
using namespace std;
 
#define endl "\n"

typedef long long int ll;
 
const int MOD = 1e9 + 7;
const int N = 100000;

int cnt = 1;
pair<int, int> id[N], mn[N];
vector<int> adj[N];
int v[N];
bool vis[N];

struct DSU{
	void init(int n){
		for(int i = 0; i < n; i++) v[i] = -1;
	}
	int get(int x){return v[x] < 0 ? x : v[x] = get(v[x]);}
	bool unite(int x, int y){
		x = get(x); y = get(y);
		if(x == y) return 0;
		if(v[x] > v[y]) swap(x, y);
		v[x] += v[y]; v[y] = x;
		return 1;
	}
};


void DFS(int x){
	id[x].first = cnt; cnt++;
	for(int node : adj[x]){
		if(id[node].first > 0) continue;
		DFS(node);
	}
	id[x].second = cnt; cnt++;
}

void get_ans(int x, int p){
	vis[x] = 1;
	for(int node : adj[x]){
		if(node == p) continue;
		get_ans(node, x);
		mn[x].first = min(mn[x].first, mn[node].first);
		mn[x].second = max(mn[x].second, mn[node].second);
		if(!(mn[node].first < id[node].first || mn[node].second > id[node].second)){
			cout << node + 1 << " " << x + 1 << endl;
		}
	}
}

void solve(){
	int n, m; cin >> n >> m;
	DSU UF; UF.init(n);
	vector<int> done;
	for(int i = 0; i < m; i++){
		int u, v; cin >> u >> v; u--; v--;
		if(UF.unite(v, u)) {adj[u].push_back(v); adj[v].push_back(u); done.push_back(i);}
	}
	for(int i = 0; i < n; i++) id[i] = {0, 0};
	for(int i = 0; i < n; i++){
		if(id[i].first == 0){
			DFS(i);
		}
	}
	rewind(stdin);
	cin >> n >> m;
	for(int i = 0; i < n; i++) mn[i] = {id[i].first, id[i].second};
	int ind = 0;
	for(int i = 0; i < m; i++){
		int u, v; cin >> u >> v; u--; v--;
		if(ind < (int)done.size() && done[ind] == i){
			ind++; continue;
		}
		mn[u].first = min(mn[u].first, id[v].first);
		mn[u].second = max(mn[u].second, id[v].second);
		mn[v].first = min(mn[v].first, id[u].first);
		mn[v].second = max(mn[v].second, id[u].second);
	}
	for(int i = 0; i < n; i++) vis[i] = 0;
	for(int i = 0; i < n; i++){
		if(!vis[i]){
			get_ans(i, -1);
		}
	}
}

signed main(){
    //~ ios_base::sync_with_stdio(0);
    cin.tie(0);

    //~ int tt; cin >> tt;
    int tt = 1;
    for(int t = 1; t <= tt; t++){
        solve();
    }
}

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Correct 2 ms 2660 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 14 ms 2960 KB Output is correct
2 Correct 13 ms 2996 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 500 ms 3300 KB Output is correct
2 Correct 507 ms 3404 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 914 ms 3668 KB Output is correct
2 Correct 1004 ms 3656 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1363 ms 4588 KB Output is correct
2 Correct 1140 ms 4676 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1678 ms 6924 KB Output is correct
2 Correct 1453 ms 6512 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2657 ms 7228 KB Output is correct
2 Correct 2666 ms 7296 KB Output is correct

Subtask #8
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 3508 ms 8264 KB Output is correct
2 Correct 3250 ms 8536 KB Output is correct

Subtask #9
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 4460 ms 8120 KB Output is correct
2 Correct 4225 ms 8128 KB Output is correct

Subtask #10
0 / 10.0

# Verdict Execution time Memory Grader output
1 Execution timed out 5017 ms 7772 KB Time limit exceeded
2 Halted 0 ms 0 KB -