vijos1022Victoria的舞会2——by rfy

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强连通裸题

#include<cstdio>#include<vector>#include<algorithm>using namespace std;vector<int> ljb[200000],nljb[200000],jh[200000];int n,m,i,x,y,wz,zn,ans,bcnt,dfn[200000],belong[200000],instack[200000],low[200000],dindex,stap[200000],stop;void tarjan(int i){    dfn[i]=low[i]=++dindex;    instack[i]=1;    stap[++stop]=i;    vector<int>::iterator iv;    for (iv=ljb[i].begin();iv!=ljb[i].end();iv++){        if (!dfn[*iv]){            tarjan(*iv);            if (low[*iv]<low[i])                low[i]=low[*iv];        }        else if (instack[*iv]&&dfn[*iv]<low[i])            low[i]=dfn[*iv];    }    if (dfn[i]==low[i]){        bcnt++;        int j;        do{            j=stap[stop--];            instack[j]=0;            belong[j]=bcnt;            jh[bcnt].push_back(j);        }        while (j!=i);    }}void work(){    int i;    for (i=1;i<=n;i++)        if (!dfn[i])            tarjan(i);    printf("%d\n",bcnt);}int main(){    scanf("%d",&n);    for (i=1;i<=n;i++){        scanf("%d",&x);        while (x){            ljb[i].push_back(x);            scanf("%d",&x);        }    }        work();}

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