tarjan缩点
整理了下模板。。。
1 #include<iostream> 2 #include<cstdio> 3 #include<cmath> 4 #include<algorithm> 5 #include<queue> 6 #include<cstring> 7 #define PAU putchar(' ') 8 #define ENT putchar('\n') 9 using namespace std; 10 const int maxn=100000+10,maxm=500000+10; 11 int low[maxn],dfn[maxn],s[maxn],beg[maxn],top,scc,cz;bool ins[maxn]; 12 struct ted{int x,y;ted*nxt;}adj[maxm],*fch[maxn],*ms=adj; 13 void add(int x,int y){*ms=(ted){x,y,fch[x]};fch[x]=ms++;return;} 14 void tarjan(int u){ 15 low[u]=dfn[u]=++cz;ins[u]=true;s[++top]=u; 16 for(ted*e=fch[u];e;e=e->nxt){ 17 int v=e->y;if(!dfn[v])tarjan(v),low[u]=min(low[u],low[v]); 18 else if(ins[v])low[u]=min(low[u],dfn[v]); 19 }if(low[u]==dfn[u]){ 20 scc++;int t=-1;while(t!=u)beg[t=s[top--]]=scc,ins[t]=false; 21 }return; 22 } 23 inline int read(){ 24 int x=0,sig=1;char ch=getchar(); 25 while(!isdigit(ch)){if(ch=='-')sig=-1;ch=getchar();} 26 while(isdigit(ch))x=10*x+ch-'0',ch=getchar(); 27 return x*=sig; 28 } 29 inline void write(int x){ 30 if(x==0){putchar('0');return;}if(x<0)putchar('-'),x=-x; 31 int len=0,buf[15];while(x)buf[len++]=x%10,x/=10; 32 for(int i=len-1;i>=0;i--)putchar(buf[i]+'0');return; 33 } 34 int n,m; 35 void init(){ 36 n=read();m=read();int x,y; 37 while(m--){x=read();y=read();add(x,y);} 38 for(int i=1;i<=n;i++) if(!dfn[i]) tarjan(i); 39 for(int i=1;i<=n;i++){ 40 printf("%d:%d\n",i,beg[i]); 41 } 42 return; 43 } 44 void work(){ 45 return; 46 } 47 void print(){ 48 return; 49 } 50 int main(){init();work();print();return 0;} 51 /* 52 5 5 53 1 2 54 2 3 55 3 4 56 4 5 57 5 1 58 */
