## Solución al problema número 796 de UVA - 796.

Cualquier duda no dudes en contactar.

``````#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
const ll oo = 0x3f3f3f3f3f3f3f3fLL;

#define FOR(i, a, b) for(int i = (a); i < int(b); i++)
#define FORD(i, a, b) for(int i = (b)-1; i >= int(a); i--)
#define has(c, e) ((c).find(e) != (c).end())
#define sz(c) int((c).size())
#define all(c) c.begin(), c.end()

struct Edge{
int u, v;
};

void ArticulationPointandBridges(vector<vi>& adj, vector<Edge> E, vi& articulation, vi& bridges) {
int n = sz(adj), m = sz(E);
articulation = vi(n, -1);
bridges = vi(m, -1);
vi dfs_low(n, -1), dfs_num(n ,-1), parent(n, -1);
articulation = vi(n, 0);
bridges = vi(m, 0);
int dfsroot, rootc, cnt = 0;
function<void(int)> ABdfs = [&](int u) {
dfs_num[u] = dfs_low[u] = cnt++;
int v = E[t].u^E[t].v^u;
if(dfs_num[v] == -1){
if(u == dfsroot) rootc++;
parent[v] = t;
ABdfs(v);
dfs_low[u] = min(dfs_low[u], dfs_low[v]);
if(dfs_low[v] >= dfs_num[u])articulation[u] = 1;
if(dfs_low[v] > dfs_num[u]) bridges[t] = 1;
} else if (t != parent[u]){
dfs_low[u] = min(dfs_low[u], dfs_num[v]);
}
}
};
FOR(i, 0, n) {
if(dfs_num[i] == -1) {
rootc = 0, dfsroot = i;
ABdfs(i);
if (rootc <= 1) articulation[i] = 0;
}
}
}

bool cmp(Edge a,Edge b)
{
if(a.u == b.u) return a.v<b.v;
return a.u<b.u;
}

Edge reverse(Edge e){
if (e.u>e.v){
return Edge{e.v,e.u};
}
return e;
}

int main() {
int n,m;
while(scanf("%d",&n)==1)
{
vector<Edge> E;
vi articulation;
vi bridge;
bool connected[n+1][n+1];
memset(connected,false, sizeof(connected));
for(int i=0; i<n;i++)
{
int x,y; scanf("%d (%d)",&x,&m);
for(int j=0; j<m;j++)
{
scanf("%d",&y);
if(connected[x][y] || connected[y][x] ) continue;
connected[x][y] = true;
E.push_back({x,y});
}
}

int cnt = 0;
vector<Edge> resu;

for(unsigned i=0;i<bridge.size();i++)
if(bridge[i]==1) {
cnt++;
resu.push_back(reverse(E[i]));
}

sort(resu.begin(),resu.end(),cmp);

for(int i=0; i<cnt;i++)
printf("%d - %d\n", resu[i].u,resu[i].v);
cin.ignore();

printf("\n");
}
return 0;
}
``````