oj.uz

Submission #396317

# Submission time Handle Problem Language Result Execution time Memory
396317 2021-04-29T18:16:07 Z The_Blitz Pipes (CEOI15_pipes) C++17
100 / 100
 1418 ms 13960 KB 
// 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[100001];

int g_low[100001];
int g_num[100001];

int P[2][100001];
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]);
		}
        
		else 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
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2636 KB Output is correct
2 Correct 2 ms 2636 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 3148 KB Output is correct
2 Correct 6 ms 2892 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 114 ms 3004 KB Output is correct
2 Correct 109 ms 2868 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 191 ms 3712 KB Output is correct
2 Correct 259 ms 3188 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 327 ms 5272 KB Output is correct
2 Correct 293 ms 4888 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 477 ms 10552 KB Output is correct
2 Correct 400 ms 7084 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 710 ms 11776 KB Output is correct
2 Correct 709 ms 8916 KB Output is correct

Subtask #8
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1020 ms 13960 KB Output is correct
2 Correct 872 ms 9008 KB Output is correct

Subtask #9
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1152 ms 13848 KB Output is correct
2 Correct 1072 ms 9028 KB Output is correct

Subtask #10
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1375 ms 13300 KB Output is correct
2 Correct 1418 ms 10568 KB Output is correct