bridge, flashlight, 4 people, 17 minutes

#!/usr/bin/env python

# Four men want to cross a bridge.  The bridge is of a width such that a 
# maximum of 2 people may cross at a time.  
# 
# One man takes 10 minutes to cross, another takes 5 minutes to cross,
# another takes 2 minutes to cross, and the last takes 1 minute to 
# cross.

# I will call these men A, B, C, and D, respectively.
# 
# Here is the catch.  If two people cross the bridge together, they must 
# walk at the pace of the slower one. So if A and B cross, they take 10 
# minutes. Also, it is night. Each trip requires a flashlight.  There 
# is only one flashlight. The men are not allowed to toss the light over 
# the river.
# 
# How fast can you get all 4 men over the bridge?

import random

class Point(object):
    
    def __init__(self, name=None, init=None):
        self.name = name
        self.people = init
    
    def send(self, people, to=None):
        for p in people:
            self.people.remove(p)
        to.people += people
        print people, "from", self.name, "to", to.name
        return max(people)
    
    def __str__(self):
        return self.name

if __name__ == '__main__':
    acc, counter = 10000, 0
    while acc > 17:
        acc = 0
        a = Point(name='A', init=[1, 2, 5, 10])
        b = Point(name='B', init=[])
        while True:
            chosen = random.sample(a.people, 2)
            acc += a.send(chosen, to=b)
            if not a.people:
                break
            chosen = random.sample(b.people, 1)
            acc += b.send(chosen, to=a)
        print acc
        counter += 1
    print "Sol'n found after", counter, "iterations."