有向图强连通分支(bfs邻接阵形式).txt

normal template for acm/ICPC

//有向图强连通分支,bfs邻接阵形式,O(n^2)
//返回分支数,id返回1..分支数的值
//传入图的大小n和邻接阵mat,不相邻点边权0
#define MAXN 100

int find_components(int n,int mat[][MAXN],int* id){
	int ret=0,a[MAXN],b[MAXN],c[MAXN],d[MAXN],i,j,k,t;
	for (k=0;k<n;id[k++]=0);
	for (k=0;k<n;k++)
		if (!id[k]){
			for (i=0;i<n;i++)
				a[i]=b[i]=c[i]=d[i]=0;
			a[k]=b[k]=1;
			for (t=1;t;)
				for (t=i=0;i<n;i++){
					if (a[i]&&!c[i])
						for (c[i]=t=1,j=0;j<n;j++)
							if (mat[i][j]&&!a[j])
								a[j]=1;
					if (b[i]&&!d[i])
						for (d[i]=t=1,j=0;j<n;j++)
							if (mat[j][i]&&!b[j])
								b[j]=1;
				}
			for (ret++,i=0;i<n;i++)
				if (a[i]&b[i])
					id[i]=ret;
		}
	return ret;
}