一般图最大匹配 带花树算法 模板

例题：uoj #79. 一般图最大匹配

板子：

#include<set>#include<map>#include<deque>#include<queue>#include<stack>#include<cmath>#include<ctime>#include<bitset>#include<string>#include<vector>#include<cstdio>#include<cstdlib>#include<cstring>#include<climits>#include<complex>#include<iostream>#include<algorithm>#define ll long longusing namespace std;const int maxn = 11000;const int maxm = 510000;int n,m;struct edge{    int y,nex;    edge(){}    edge(const int _y,const int _nex){y=_y;nex=_nex;}}a[maxm]; int len,fir[maxn];inline void ins(const int x,const int y){a[++len]=edge(y,fir[x]);fir[x]=len;}int fa[maxn];int findfa(const int x){return fa[x]==x?x:fa[x]=findfa(fa[x]);}void unit(int x,int y){fa[x=findfa(x)]=findfa(y);}int nex[maxn],spouse[maxn],mark[maxn],v[maxn],cnt;int LCA(int x,int y){    ++cnt;    while(x)    {        v[x=findfa(x)]=cnt;        x=nex[spouse[x]];    }    while(y)    {        if(v[y=findfa(y)]==cnt) return y;        y=nex[spouse[y]];    }}int q[maxn],tail;void group(int x,const int &tp){    while(x!=tp)    {        int b=spouse[x],c=nex[b];        if(findfa(c)!=tp) nex[c]=b;        if(mark[b]==2) mark[q[++tail]=b]=1;        if(mark[c]==2) mark[q[++tail]=c]=1;        unit(x,b); unit(b,c);        x=c;    }}bool augment(const int s){    for(int i=1;i<=n;i++) mark[i]=nex[i]=0,fa[i]=i;    q[tail=1]=s;    for(int i=1;i<=tail;i++)    {        const int x=q[i];        for(int k=fir[x];k;k=a[k].nex)        {            const int y=a[k].y; if(spouse[y]==x) continue;            if(findfa(x)==findfa(y)) continue;            if(mark[y]==2) continue;            if(mark[y]==0)            {                if(!spouse[y])                {                    int p1=y,p2=x;                    while(p1)                    {                        int z=spouse[p2];                        spouse[p1]=p2; spouse[p2]=p1;                        p1=z,p2=nex[p1];                    }                    return true;                }                else                {                    nex[y]=x;                    mark[y]=2;                    mark[q[++tail]=spouse[y]]=1;                }            }            else            {                int tp=LCA(x,y);                if(findfa(x)!=tp) nex[x]=y;                if(findfa(y)!=tp) nex[y]=x;                group(x,tp); group(y,tp);            }        }    }    return false;}int main(){    scanf("%d%d",&n,&m);    for(int i=1;i<=m;i++)    {        int x,y; scanf("%d%d",&x,&y);        ins(x,y); ins(y,x);    }    int re=0;    for(int i=1;i<=n;i++)        if(!spouse[i]&&augment(i)) re++;    printf("%d\n",re);    for(int i=1;i<=n;i++) printf("%d ",spouse[i]);    return 0;}