oj.uz

Submission #948574

# Submission time Handle Problem Language Result Execution time Memory
948574 2024-03-18T07:57:21 Z vjudge1 Pipes (CEOI15_pipes) C++17
20 / 100
 5000 ms 51024 KB 
#include <bits/stdc++.h>

#define int int16_t
#define ff first
#define ss second
#define pb push_back
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define rnd(l, r) uniform_int_distribution<int>(l, r)(rng)
using namespace std;


const int N = 10000 + 2;

int16_t tin[N], tout[N];
int16_t low[N];
bool used[N];
vector <int16_t> g[N];

int16_t timer;
struct hash_pair {
    template <class T1, class T2>
    size_t operator()(const pair<T1, T2>& p) const
    {
        auto hash1 = hash<T1>{}(p.first);
        auto hash2 = hash<T2>{}(p.second);
 
        if (hash1 != hash2) {
            return hash1 ^ hash2;              
        }
         
        // If hash1 == hash2, their XOR is zero.
          return hash1;
    }
};
unordered_map <int16_t,int16_t> mp[N], cant[N];
//unordered_map<pair<int, int>, bool, hash_pair> mp, cant;
int n;
int32_t m;

void dfs_low(int16_t v, int16_t p = -1){
    used[v] = true;
    tin[v] = low[v] = ++timer;
    for (auto u : g[v]){
        if (u == p) continue;
        if (used[u]){
            low[v] = min(low[v], tin[u]);
        }else{
            dfs_low(u, v);
            low[v] = min(low[v], low[u]);
            if (low[u] > tin[v] &&  !cant[min(v, u)].count(max(v, u))){
				cout << min(v, u) <<" "<< max(v, u) << "\n";
			}
        }
    }
}

main(){
	iostream::sync_with_stdio(false);	
    cin.tie(nullptr);
	cout.tie(nullptr);
	cin >> n >> m;
	for(int i = 0; i < m; i++){
		int16_t a, b;
		cin >> a >> b;
		if(a > b)swap(a, b);
		if(mp[a].count(b)){
			cant[a][b] = 1;
			continue;
		}
		g[a].pb(b);
		g[b].pb(a);
		mp[a][b] = 1;
	}
	
	for(int i = 1; i <= n; i++){
		if(!used[i]){
			dfs_low(i);
		}
	}
}    
/*
 * Before implementing the problem:
	
	Do I understand the problem correctly?
	Which places are tricky? What do I need to remember to implement them correctly?
	Which place is the heaviest by implementation? Can I do it simpler?
	Which place is the slowest? Where do I need to be careful about constant factors and where I can choose slower but simpler implementation?
	----------------------------------
	If not AC:
 
	Did you remember to do everything to handle the tricky places you thought about before?
	Is the solution correct?
	Do I understand the problem correctly?
	----------------------------------
	If you have a test on which the solution gives wrong answer:
 
	Is the solution doing what it was supposed to do?
	Is the problem in the code or in the idea?
*/

Compilation message

pipes.cpp:58:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   58 | main(){
      | ^~~~

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 1628 KB Output is correct
2 Correct 1 ms 1628 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 2908 KB Output is correct
2 Correct 4 ms 2652 KB Output is correct

Subtask #3
0 / 10.0

# Verdict Execution time Memory Grader output
1 Execution timed out 5049 ms 31448 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #4
0 / 10.0

# Verdict Execution time Memory Grader output
1 Execution timed out 5090 ms 51024 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #5
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 2 ms 3164 KB Execution killed with signal 11
2 Halted 0 ms 0 KB -

Subtask #6
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 2 ms 3164 KB Execution killed with signal 11
2 Halted 0 ms 0 KB -

Subtask #7
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 2 ms 3420 KB Execution killed with signal 11
2 Halted 0 ms 0 KB -

Subtask #8
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 2 ms 3164 KB Execution killed with signal 11
2 Halted 0 ms 0 KB -

Subtask #9
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 2 ms 3160 KB Execution killed with signal 11
2 Halted 0 ms 0 KB -

Subtask #10
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 3 ms 3164 KB Execution killed with signal 11
2 Halted 0 ms 0 KB -