Submission #959101

#	Time	Username	Problem	Language	Result	Execution time	Memory
959101		Cyber_Wolf	Pipes (CEOI15_pipes)	C++17	30 / 100	840 ms	65536 KiB

pipes

#include <bits/stdc++.h>
 
using namespace std;
 
#define fastio ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
 
const int N = 1e5+5;
 
vector<int> adj[N];
int n, m, tin[N], tmp, par[2][N], sz[2][N];

int get(int src, int t)
{
	if(src == par[t][src])	return src;
	return par[t][src] = get(par[t][src], t);
}

bool join(int u, int v, int t)
{
	u = get(u, t), v = get(v, t);
	if(u == v)	return false;
	if(sz[t][u] > sz[t][v])	swap(u, v);
	par[t][u] = v;
	sz[t][v] += sz[t][u];
	return true;
}
 
int dfs(int src, int pa = -1)
{
	int low, idx = 0;
	tin[src] = low = ++tmp;
	for(auto it : adj[src])
	{
		if(it == pa)
		{
			idx++;	
			continue;
		}
		if(tin[it])
		{
			low = min(low, tin[it]);
			idx++;	
			continue;
		}
		int low_it = dfs(it, src);
		low = min(low, low_it);
		if(idx && adj[src][idx-1] == it)	
		{
			idx++;
			continue;
		}
		if(idx+1 < adj[src].size() && adj[src][idx+1] == it)	
		{
			idx++;
			continue;
		}
		if(low_it > tin[src])
		{
			cout << src << ' ' << it << endl;
		}
		idx++;		
	}
	return low;
}
 
int main()
{
	fastio;
	cin >> n >> m;
	for(int i = 1; i <= n; i++)	par[0][i] = par[1][i] = i, sz[0][i] = sz[1][i] = 1;
	for(int i = 0; i < m; i++)
	{
		int u, v;
		cin >> u >> v;
		if(join(u, v, 0) || join(u, v, 1))
			adj[u].push_back(v), adj[v].push_back(u);
	}
	for(int i = 1; i <= n; i++)	sort(adj[i].begin(), adj[i].end());
	for(int i = 1; i <= n; i++)
	{
		if(!tin[i])	dfs(i);
	}
 
    return 0;
}

Compilation message (stderr)

pipes.cpp: In function 'int dfs(int, int)':
pipes.cpp:52:12: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   52 |   if(idx+1 < adj[src].size() && adj[src][idx+1] == it)
      |      ~~~~~~^~~~~~~~~~~~~~~~~

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