We present the first randomized O(log n) time and O(m + n) work EREW PRAM a
lgorithm for finding a spanning forest of an undirected graph G = (V, E) wi
th n vertices and m edges. Our algorithm is optimal with respect to time, w
ork, and space. As a consequence we get optimal randomized EREW PRAM algori
thms for other basic connectivity problems such as finding a bipartite part
ition, finding bridges and biconnected components, finding Euler tours in E
ulerian graphs, finding an ear decomposition, finding an open ear decomposi
tion, finding a strong orientation, and finding an st-numbering, (C) 2001 A
cademic Press.