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lukasvermeer

# simulation to solve puzzle posed in https://www.twitter.com/jben0/status/1088146700735139840

k = 10

# enumerate all potential combinations of flips
# (also copies first two students to end of the string to fake a circle)
f = map(x->(x^2)[1:k+2],[ bitstring(n)[65-k:64] for n in 0:2^k-1 ])

# condition on at least one student with heads on either side
c = filter(l->size(collect(eachmatch(r"1.1",l)),1)>0,f)