minTime.py

import itertools;

permutations = itertools.permutations([100,250,1000, 1200]);

times = []

for it in permutations :
	print it
	presum = 0;
	roundTrip = []
	sums = [];
	for i in range(len(it)) :
		el = it[i];
		presum += el;
		if (i!=0) : roundTrip.append(presum)
	print roundTrip

	times.append(sum(roundTrip))

print times

print 'minimum time', min(times);