optlangで https://twitter.com/ishihara716/status/813384884534145024 を解く

a.py

#!/usr/bin/env python2

from optlang.glpk_interface import Model, Variable, Constraint, Objective

def diff(u, v, b, model):
	model.add(Constraint((u - v) - 100 * b,       ub = -1))
	model.add(Constraint((v - u) - 100 * (1 - b), ub = -1))

model = Model(name = "Simple model")

m1 = Variable("m1", type = "integer")
m0 = Variable("m0", lb = 0, ub = 9, type = "integer")
month = 10 * m1 + m0

d1 = Variable("d1", type = "integer")
d0 = Variable("d0", lb = 0, ub = 9, type = "integer")
day = 10 * d1 + d0

H1 = Variable("H1", type = "integer")
H0 = Variable("H0", lb = 0, ub = 9, type = "integer")
hour = 10 * H1 + H0

M1 = Variable("M1", type = "integer")
M0 = Variable("M0", lb = 0, ub = 9, type = "integer")
minute = 10 * M1 + M0

S1 = Variable("S1", type = "integer")
S0 = Variable("S0", lb = 0, ub = 9, type = "integer")
sec = 10 * S1 + M0

model.add(Constraint(month, lb = 1, ub = 12))
model.add(Constraint(day, lb = 1, ub = 31))
model.add(Constraint(hour, lb = 0, ub = 23))
model.add(Constraint(minute, lb = 0, ub = 59))
model.add(Constraint(sec, lb = 0, ub = 59))
model.objective = Objective((((month * 31 + day) * 24 + hour) * 60 + minute) * 60 + sec, direction = "min")

l = [m1, m0, d1, d0, H1, H0, M1, M0, S1, S0]
count = 0
for i in range(len(l)):
	for j in range(len(l)):
		if i >= j:
			continue
		diff(l[i], l[j], Variable("bv" + str(count), type = "binary"), model)
		count += 1

model.optimize()
print "status:", model.status
for var_name, var in model.variables.iteritems():
	print var_name, "=", var.primal

print("Result: %d%d/%d%d %d%d:%d%d:%d%d" % (
	m1.primal,
	m0.primal,
	d1.primal,
	d0.primal,
	H1.primal,
	H0.primal,
	M1.primal,
	M0.primal,
	S1.primal,
	S0.primal
))

result.txt

Result: 03/26 17:48:59

How to specify an unequal constraint with an Integer Linear Programming (ILP) solver http://www.yzuda.org/Useful_Links/optimization/unequal.html