Submission #451222

#	Time	Username	Problem	Language	Result	Execution time	Memory
451222		ak2006	Pipes (CEOI15_pipes)	C++14	10 / 100	1576 ms	28024 KiB

pipes

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vb = vector<bool>;
using vvb = vector<vb>;
using vi = vector<int>;
using vvi = vector<vi>;
using vl = vector<ll>;
using vvl = vector<vl>;
using vc = vector<char>;
using vvc = vector<vc>;
using vs = vector<string>;
const ll mod = 1e9 + 7,inf = 1e18;
#define pb push_back
#define fast ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
void setIO()
{
    fast;
}
int maxN = 1e5 + 5,maxM = 6e6 + 5,n,m,TIMER;
vvi adj(2 * maxN);
vb vis(maxN);
vi low(maxN),in(maxN),p1(maxN),p2(maxN);
vvi bridges;
int Find1(int u)
{
    if (p1[u] == u)return u;
    return p1[u] = Find1(p1[u]);
}
int Find2(int u)
{
    if (p2[u] == u)return u;
    return p2[u] = Find2(p2[u]);
}
bool Merge1(int u,int v)
{
    u = Find1(u),v = Find1(v);
    if (u == v)return false;
    p1[v] = u;
    return true;
}
bool Merge2(int u,int v)
{
    u = Find2(u),v = Find2(v);
    if (u == v)return false;
    p2[v] = u;
    return true;
}
void dfs(int u,int p)
{   
    vis[u] = 1;
    in[u] = low[u] = ++TIMER;
    for (int v:adj[u]){
        if (v == p)continue;
        if (vis[v]){
            low[u] = min(low[u],in[v]);
            continue;
        }        
        dfs(v,u);
        low[u] = min(low[u],low[v]);
        if (low[v] > in[u])
            bridges.pb({u,v});
    }
}
int main()

{
    setIO();
    cin>>n>>m;
    for (int i = 1;i<=n;i++)p1[i] = p2[i] = i;
    vvi edges;
    for (int i = 1;i<=m;i++){
        int u,v;
        cin>>u>>v;
        if (Merge1(u,v) or Merge2(u,v))
            edges.pb({u,v});
        assert((int)edges.size() <= 2 * n - 2);
    }
    m = (int)edges.size();
    for (auto it:edges){
        //cout<<it[0]<<" "<<it[1]<<endl;
        adj[it[0]].pb(it[1]),adj[it[1]].pb(it[0]);
    }
    for (int i = 1;i<=n;i++)if (!vis[i])dfs(i,-1);
    for (auto it:bridges)cout<<it[0]<<" "<<it[1]<<'\n';
    return 0;
}

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