Hackin' the Beanstalk
by Yar Woo, Asher Walkover, Ian Tullis (original concept)
Answer: SOURCE FILES
The team interacts with a "hacker typing" terminal; typing just a few letters causes several lines of computer code to display. Someone who knows computer science may recognize some of the code-snippets: they come from implementations of real algorithms, including some pretty-famous ones.
Further exploration may reveal that entering the name of the computer scientist an algorithm's named for displays the code for a function implementing that algorithm. E.g., typing in bresenham displays code for Bresenham's line-drawing algorithm. The "banner" text at the start hints at algorithms; e.g., "Finding the best way through the woods..." suggests DIJKSTRA's shortest-path algorithm.
Very careful examination reveals that each function contains an error. For each algorithm, the team wants to "extract" the letter they typed when the error appeared. E.g., in DIJKSTRA's algorithm, the bad code appears when you type S, so extract S.
| Algorithm | Present Code | Correct Code | Wrong-code letter |
|---|---|---|---|
| BRESENHAM | if dx < dy | if dx > dy | brEsenham |
| CHUDNOVSKY | for k in range(1, maxK): | for k in range(0, maxK): | chUdnovsky |
| DIJKSTRA | unvisited[min_node] < unvisited[node]: | unvisited[min_node] > unvisited[node]: | dijkStra |
| EUCLID | return b | return a | euClid |
| FLOYD | return 0, 0 | return 1, 0 | Floyd |
| GALE-SHAPLEY | matches[w] = 0 | matches[w] = m | gale-Shapley |
| KADANE | running_sum = i | running_sum = 0 | kadanE |
| LUHN | parity_check = num_digits ^ 2 | parity_check = num_digits % 2 | Luhn |
| POLLARD | g = lambda x: (x*x + 1) % x | g = lambda x: (x*x + 1) % n | pOllard |
| TARJAN | if index >= lowlinks[node]: | if index == lowlinks[node]: | taRjan |
| VITERBI | x[i - 1] = T2[x[0], i] | x[i - 1] = T2[x[i], i] | viterbI |
Ordering based on the algorithm-clues in the "banner" text gives the answer:
| Finding the best way through the woods | dijkStra |
| Planning the best way to divide up all these beans equally | pOllard |
| Calculating the area of the circular field | chUdnovsky |
| Asking around to see which of the townspeople know each other really well | taRjan |
| Figuring out the proper fraction of crops to rotate this year | euClid |
| Determining which contiguous section of land produced the most wheat | kadanE |
| Seeing if the beanstalk has any loops in it | Floyd |
| Trying to determine the most likely thing the giant said | viterbI |
| Verifying the bean/cow transaction | Luhn |
| Drawing the beanstalk as a straight line | brEsenham |
| Pairing cows and bulls | gale-Shapley |
The letters spell out SOURCE FILES, the puzzle's solution.