int atoi( char* pStr )

Problem: write the definition for this function without using any built-in functions. if pStr is null, return 0. if pStr contains non-numeric characters, either return 0 (ok) or return the number derived so far (better) (e.g. if its “123A”, then return 123). assume all numbers are positive. plus or minus signs can be considered non-numeric… Read More »

Daughters’ Ages

Two MIT math grads bump into each other at Fairway on the upper west side. They haven’t seen each other in over 20 years. the first grad says to the second: “how have you been?”second: “great! i got married and i have three daughters now”first: “really? how old are they?”second: “well, the product of their… Read More »

Palindromes

Problem: this year on October 2, 2001, the date in MMDDYYYY format will be a palindrome (same forwards as backwards).10/02/2001when was the last date that this occurred on? (see if you can do it in your head!) Solution olution: we know the year has to be less than 2001 since we already have the palindrome… Read More »

Sum it Up

Problem: you are given a sequence of numbers from 1 to n-1 with one of the numbers repeating only once. (example: 1 2 3 3 4 5). how can you find the repeating number? what if i give you the constraint that you can’t use a dynamic amount of memory (i.e. the amount of memory you use can’t… Read More »

Pirates

Five pirates have 100 gold coins. they have to divide up the loot. in order of seniority (suppose pirate 5 is most senior, pirate 1 is least senior), the most senior pirate proposes a distribution of the loot. they vote and if at least 50% accept the proposal, the loot is divided as proposed. otherwise… Read More »

Fog Creek Programmers

100 fogcreek programmers are lined up in a row by an assassin. the assassin puts red and blue hats on them. they can’t see their own hats, but they can see the hats of the people in front of them. the assassin starts in the back and says “what color is your hat?” the fogcreek programmer… Read More »

Bad King

A bad king has a cellar of 1000 bottles of delightful and very expensive wine. A neighbouring queen plots to kill the bad king and sends a servant to poison the wine. (un)fortunately the bad king’s guards catch the servant after he has only poisoned one bottle. Alas, the guards don’t know which bottle but… Read More »

Jelly Beans

You have three jars that are all mislabeled. one contains peanut butter jelly beans, another grape jelly jelly beans, and the third has a mix of both (not necessarily a 50/50 mix, could be a 1/99 mix or a 399/22 mix). how many jelly beans would you have to pull out, and out of which… Read More »

Bridge

Problem: this one is a classic that many of you have probably already heard, but all the more reason why it should definitely be included here. four people are on this side of the bridge. the bridge will be destroyed by a bomb in 17 minutes. everyone has to get across before that. problem is… Read More »

Card Trick Without the Trick

This is a card trick without the trick. there is no sleight of hand, no tricks up my sleeve, no magic whatsoever. it’s all done with logic, yet it will amaze most people. Joel and i are working together as a team to do the trick. Babak will be the culprit.