Bridges in a connected graph

Question

I have a programming task(not homework.) where I have to find the bridges in a graph. I worked on it a bit myself, but could not come up with anything satisfactory. So i goo

Answer 1

Not a new answer, but I needed this in Python. Here's a translation of the algorithm for an undirected NetworkX Graph object G:

def bridge_dfs(G,u,v,cnt,low,pre,bridges):
    cnt    += 1
    pre[v]  = cnt
    low[v]  = pre[v]

    for w in nx.neighbors(G,v):
        if (pre[w] == -1):
            bridge_dfs(G,v,w,cnt,low,pre,bridges)

            low[v] = min(low[v], low[w])
            if (low[w] == pre[w]):
                bridges.append((v,w))

        elif (w != u):
            low[v] = min(low[v], pre[w])

def get_bridges(G):
    bridges = []
    cnt     = 0
    low     = {n:-1 for n in G.nodes()}
    pre     = low.copy()

    for n in G.nodes():
         bridge_dfs(G, n, n, cnt, low, pre, bridges)

    return bridges # <- List of (node-node) tuples for all bridges in G

Be careful of Python's recursion depth limiter for large graphs...