[Drizzleqyy's SECOND HIDE]

*** The container is not at the posted coordinates ***

During Sonia(@Wochilizhi)'s trip to Harvard University, she found an amazing photo spot nearby. She decided to keep it as a secret and see if I can figure out where the spot is by myself. With a picture she took at the spot as a clue, I hanged out around the Harvard square for an afternoon, but still no clue. On the other day, I walked out from a nearby AT&T store, and suddenly noticed that the park in front of me is exactly where the spot is. The place later became my favorite place around the Harvard campus. I then decided to hide a cache here, as a souvenir for Sonia and me.

The photo spot is at the posted coordinates. You may slightly adjust your position to get a better view. It is also strongly recommended to sit at a bench around and enjoy a peaceful afternoon.

Caching Instruction:

This cache has a total of 3 stages. You do not need to complete the first two stages in order, but completing them in order will guide you a smooth tour across the Harvard yard.

Even though the puzzle is related to Computer Science, there is no computing background needed to solve it!

It is suggested to read through the instruction before starting caching.

Stage 1:

Get to Sonia's photo spot and take a photo facing South. 

Look for a word in the photo (yes!), and don't forget it!

(The word will be explicitly shown on the photo, so no decoding is needed for this part.)

Stage 2: (Pens and papers will help)

Go to the Waypoint for stage 2, and you will see a black tablet. 

Combine the old name and the full new name of the building, ignoring spaces and cases.

You shouldn't leave out any articles within the names.

(Hardest Part)

Count the number of occurrence of each letter appears in the combined name. Sort them in alphabetical order and only use the very first letter for the same number of occurrence. (e.g. If M, A, and X all appear only once, use A and delete all other letters with the same number of occurrence). Combine all the used letters together, in an ascending order of their numbers of occurrence(not alphabetical). (e.g. If D appears once, P appears 3 times, C appears twice, then the result will be DCP)

Next, use Huffman Encoding to represent each letter in the combined result with a binary number. It is recommended to encode by constructing a Huffman tree. Use the binary numbers obtained from the Huffman encoding to represent each letter in the word from Stage 1. (e.g. If the word from Stage 1 is "cache", the representation for the word might be 011101001000 if you get c=01, a=11, h=001, e=000 from stage 2, using the encoding method) (Do not rely on this example to obtain the binary numbers for each letter, since binary representation changes with different text context <in this case the name of the building> while using Huffman Encoding)

Two letters in the word found in Stage 1 are not included in the combined result. Thus, you should use the letters themselves instead of binary numbers.

Stage 3:

Your answer should be the word you found from the 1st stage plus the result from Stage 2(e.g. Max10000111). Check you answer on Certitude to get the final coordinates and look for the container!

Logging Requirements:  

1. Find the cache and sign.
2. Post your found log with the photo taken at the photo spot.

It would be so nice if geocachers can see how the photo spot looks like in different seasons!

Please use stealth at the final coordinates, and avoid acting suspiciously while searching.

Don't forget to put 'favorite' if you like the photo spot! Enjoy!
 

You can validate your puzzle solution with certitude.