[Connected graph] links an undirected graph node and a bridge Tarjan to connect tarjan.

[Connected graph] links an undirected graph node and a bridge Tarjan to connect tarjan.

#include <cstdio>#include <cstring>#include <algorithm>using namespace std;const int N = 1e5, M = 1e5;struct Edge {    int v, next, idx;    Edge(){}    Edge(int _v, int _next, int _idx):        v(_v), next(_next), idx(_idx){}}e[M];int low[N], dfn[N], deep, head[N], tot;bool iscut[N], isbri[M];void __init__(){    tot = deep = 0;    memset(head, -1, sizeof(head));    memset(iscut, 0, sizeof(iscut));}void add(int u, int v, int idx){    e[tot++] = Edge(v, head[u], idx);    head[u] = tot++;}int dfs(int u, int fa){    int lowu = dfn[u] = ++deep;    int cnt = 0;    for(int i = head[u]; ~i; i = e[i].next) {        int v = e[i].v;        if(!dfn[v]) {            cnt++;            int lowv = dfs(v, u);            lowu = min(lowu, lowv);            if(lowv >= dfn[u]) iscut[u] = true;            if(lowv > dfn[u]) isbri[e[i].idx] = true;            continue ;        }        if(dfn[v] < dfn[u] && v != fa)            lowu = min(lowu, dfn[v]);    }    if(fa == -1 && cnt == 1) iscut[u] = false;    return low[u] = lowu;}int main(){    __init__();    return 0;}