一般图匹配(邻接表形式).txt

ACM资料大集合

//一般图最大匹配,邻接表形式,复杂度O(n*e)
//返回匹配顶点对数,match返回匹配,未匹配顶点match值为-1
//传入图的顶点数n和邻接表list
#define MAXN 100
struct edge_t{
	int from,to;
	edge_t* next;
};

int aug(int n,edge_t* list[],int* match,int* v,int now){
	int t,ret=0;edge_t* e;
	v[now]=1;
	for (e=list[now];e;e=e->next)
		if (!v[t=e->to]){
			if (match[t]<0)
				match[now]=t,match[t]=now,ret=1;
			else{
				v[t]=1;
				if (aug(n,list,match,v,match[t]))
					match[now]=t,match[t]=now,ret=1;
				v[t]=0;
			}
			if (ret)
				break;
		}
	v[now]=0;
	return ret;
}

int graph_match(int n,edge_t* list[],int* match){
	int v[MAXN],i,j;
	for (i=0;i<n;i++)
	v[i]=0,match[i]=-1;
	for (i=0,j=n;i<n&&j>=2;)
		if (match[i]<0&&aug(n,list,match,v,i))
			i=0,j-=2;
		else
			i++;
	for (i=j=0;i<n;i++)
		j+=(match[i]>=0);
	return j/2;
}