Check if a graph is bipartite

setA
setB
bipa = True
for e in edges
        if e0 in setA
                if e1 in setB
                       continue
                elif e1 in setA
                       bipa = False
                       break
                else
                       put e1 in setB

        elif e0 in setB
                if e1 in setA
                       continue
                elif e1 in setB
                       bipa = False
                       break
                else
                       put e1 in setA

        else
                if e1 in setA
                      put e0 in setB
                elif e1 in setB
                      put e0 in setA
                else
                      put e0 in setA
                      put e1 in setB