Submission #396316

#	Time	Username	Problem	Language	Result	Execution time	Memory
396316		The_Blitz	Pipes (CEOI15_pipes)	C++17	90 / 100	1390 ms	22520 KiB

pipes

// Restart
// += O(logn) ; + = O(n)
 
#include<vector>
#include<iostream>
#define fastio ios_base::sync_with_stdio(0);cin.tie(0)
using namespace std;

vector<int> G[100005];

int g_low[100005];
int g_num[100005];

int P[2][100005];
int n;
int cont = 1;

void dsu(int z){
	for(int i=1; i<=n;i++){
		P[z][i] = i;
	}
}
 
int dsu_find(int z, int x){
	if(x==P[z][x]) return x;
	P[z][x] = dsu_find(z,P[z][x]);
	return P[z][x];
}
 
bool dsu_uni(int z, int a , int b){
	int x = dsu_find(z,a);
	int y = dsu_find(z,b);
	if(x==y) return false;
	P[z][y] = x;
	G[a].push_back(b);
    G[b].push_back(a);
    return true;
} 


void dfs(int x ,int p = -1){ // p: parent
    g_low[x]=g_num[x]=cont++; // low:component ; num:visit order

    for(int v : G[x]){
    	if(v == p) continue;
    	
        if(g_num[v]==-1){
			
			dfs(v,x);
			
			if(g_low[v] > g_num[x] && dsu_find(1,v) != dsu_find(1,x)){
				cout<< x << " " << v << "\n";
			}
			g_low[x]=min(g_low[x],g_low[v]);
		}
        
		g_low[x]=min(g_low[x],g_num[v]);
		
    }
	
}



void go(){
	int m;
	cin>>n>>m;
	
	for(int i=1;i<=n;i++){
		g_low[i] = -1; g_num[i] = -1;
		P[0][i] = i; P[1][i] = i;
	}

	for(int i=1;i<=m;i++){
		int x,y; cin>>x>>y;
		if(!dsu_uni(0,x,y)){
			dsu_uni(1,x,y);
		}
	}

	for(int i=1;i<=n;i++){
		if(g_num[i] == -1) dfs(i);
	}

}

 
int main() {
  fastio;
  go();
  return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 10 / 10
• Subtask 5: 10 / 10
• Subtask 6: 10 / 10
• Subtask 7: 10 / 10
• Subtask 8: 10 / 10
• Subtask 9: 10 / 10
• Subtask 10: 0 / 10