** Chip A says: B is good, Chip B says: A is bad, Conclusion: at least one is bad
** Chip A says: B is bad, Chip B says: A is good, Conclusion: at least one is bad
** Chip A says: B is bad, Chip B says: A is bad, Conclusion: at least one is bad

Less than n/2 chips are bad. Help the professor find the good chips using as few tests as possible.
# (martin gardner, romanian ioi team selection 98) On the bottom floor of a building there are 11 wire ends. On the top floor there are the other 11 ends of the wires. An electrician has to figure out which end above matches with which end below. To accomplish this he can do two things: 1) tie any two ends together on the same floor. 2) test for a closed circuit by applying a device to two ends. What’s a method that minimizes the number of times the electrician needs to climb the stairs.