hdu3849 by recognizing these Guys, We Find social Networks useful

The number of bridge edges is not shown, and the bridge edge is output according to the problem input sequence.

Note the correspondence between the brig and the edges.

#include <iostream> #include <cstdlib> #include <cstring> #include <string> #include <cstdio > #include <cmath> #include <algorithm> #include <vector> #include <queue> #include <map > #define INF 0x3f3f3f3f#pragma COMMENT (linker, "/stack:16777216") #define EPS 1e-6#define ll long longusing namespace s TD; #define M 200003#define N 10003int head[n],num,dfn[n],low[n],n,m,idx,brig[m<<1],bum;struct edge{int St,ed,ne XT;}    E[m<<1];void addedge (int x,int y) {e[num].st=x;    E[num].ed=y;    E[NUM].NEXT=HEAD[X]; head[x]=num++;}    void Tarjan (int u,int father) {int i,v;    low[u]=dfn[u]=idx++;        for (I=head[u];i!=-1;i=e[i].next) {V=e[i].ed;        if (v==father) continue;            if (dfn[v]==-1) {Tarjan (v,u);            low[u]=low[u]>low[v]?low[v]:low[u];        if (Low[v]>dfn[u])//bum bridge corresponding to the side of the number brig[bum++]=i;    } else low[u]=low[u]>dfn[v]?dfn[v]:low[u]; }}void INIT () {memset (dfn,-1,sizeof DFN);    memset (head,-1,sizeof head); num=bum=idx=0;} String hash[n];string s1,s2;bool cmp (int a,int b) {return a<b;}    int main () {int icy,i,cnt;    scanf ("%d", &icy);        while (icy--) {scanf ("%d%d", &n,&m);        Init ();        Map<string,int> MP;        Cnt=1;            for (i=0;i<m;i++) {cin>>s1>>s2;            if (!mp[s1]) hash[cnt]=s1,mp[s1]=cnt++;            if (!mp[s2]) hash[cnt]=s2,mp[s2]=cnt++;            Addedge (Mp[s1],mp[s2]);        Addedge (Mp[s2],mp[s1]);        } Tarjan (1,-1);        for (i=1;i<=n;i++)//judgment diagram not connected if (dfn[i]==-1) break;            if (i<=n) {printf ("0\n");        Continue        } printf ("%d\n", bum);        Sort (brig,brig+bum,cmp);            for (int j=0;j<bum;j++) {i=brig[j];            if (i&1) i--; cout<