Tarjan算法求BCC（无向图连通块、割边、割点）

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http://www.byvoid.com/zhs/blog/biconnect

http://blog.csdn.net/shiqi_614/article/details/7833628

#include <stack>#include <stdio.h>#include <string.h>#include <algorithm>using namespace std;const int N = 2e3+5;const int M = 1e4+5;struct Vertex{    int head;}V[N];struct Edge{    int v,next;}E[M];int top,bcc,id,dfn[N],low[N],belong[N],sub[N];bool in[N],cut_p[N],cut_e[M];stack<int> S;void init(){    top = 0;    memset(V,-1,sizeof(V));}void add_edge(int u,int v){    E[top].v = v;    E[top].next = V[u].head;    V[u].head = top++;}void tarjan(int pre,int u){    dfn[u] = low[u] = ++id;    int cnt = 0;    S.push(u);    for(int i=V[u].head;~i;i=E[i].next)    {        int v = E[i].v;        if(v == pre)            continue;        if(!dfn[v])        {            ++cnt;            tarjan(u,v);            low[u] = min(low[u],low[v]);            if(u!=pre && dfn[u]<=low[v])            {                cut_p[u] = true;                sub[u]++;            }            if(dfn[u] < low[v])                cut_e[i] = true;        }        else            low[u] = min(low[u],dfn[v]);    }    if(dfn[u] == low[u])    {        int v;        do        {            v = S.top();            S.pop();            belong[v] = bcc;        }while(u != v);        bcc++;    }    if(u==pre && cnt>1)    {        cut_p[u] = true;        sub[u] = cnt-1;    }}void get_bcc_cutp_cute(int n){    bcc = id = 0;    memset(cut_p,false,sizeof(cut_p));    memset(cut_e,false,sizeof(cut_e));    memset(dfn,0,sizeof(dfn));    memset(sub,0,sizeof(sub));    for(int i=0;i<n;i++)        if(!dfn[i])            tarjan(i,i);}