Add intergalactic-transmission exercise #2543
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BNAndras
reviewed
Mar 7, 2025
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| Your job is to help implement the message sequencer to add the parity bit to the messages and the decoder to receive messages. | ||
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| The entire message, itself, is sequence of a number of bytes. |
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Suggested change
| The entire message, itself, is sequence of a number of bytes. | |
| The message is a sequence of bytes. |
| Your job is to help implement the message sequencer to add the parity bit to the messages and the decoder to receive messages. | ||
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| The entire message, itself, is sequence of a number of bytes. | ||
| The transmitters and receivers can only transmit and receive one byte at a time, so parity bit needs to be added every eighth bit. |
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Suggested change
| The transmitters and receivers can only transmit and receive one byte at a time, so parity bit needs to be added every eighth bit. | |
| The transmitters and receivers can only transmit and receive one byte at a time, so a parity bit needs to be added every eighth bit. |
Also as a layperson, I’m already a bit confused by bit vs byte so we may want to simplify.
| The transmitters and receivers can only transmit and receive one byte at a time, so parity bit needs to be added every eighth bit. | ||
| The algorithm for adding the bits is as follows: | ||
| 1. Divide the message bits into groups of 7, starting from the left (the message is transmitted from left to right). | ||
| 2. If the last group has less than 7 bits, append some 0s to pad the group to 7 bits. |
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| 2. If the last group has less than 7 bits, append some 0s to pad the group to 7 bits. | |
| 2. If the last group has less than 7 bits, append 0s until that group has 7 bits. |
What are the 0s signifying?
| 1. Divide the message bits into groups of 7, starting from the left (the message is transmitted from left to right). | ||
| 2. If the last group has less than 7 bits, append some 0s to pad the group to 7 bits. | ||
| 3. For each group, determine if there are an odd or even number of 1s. | ||
| 4. If the group has even number of 1s or none at all, append a 0 to the group. Otherwise, append 1 if there is odd number. |
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| 4. If the group has even number of 1s or none at all, append a 0 to the group. Otherwise, append 1 if there is odd number. | |
| 4. If the group has an even number of 1s or none at all, append a 0 to the group. Otherwise, append 1 if there is an odd number of 1s. |
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| The first group contains two 1s (an even number of 1s), so 0 is appended to the group. | ||
| The second group has none, so append 0. | ||
| The rest have three, so they append 1. |
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Suggested change
| The rest have three, so they append 1. | |
| The rest have three each, so they append 1. |
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| Trillions upon trillions of messages zip between Earth and neighboring galaxies every millisecond. | ||
| But transmitting over such long distances is tricky. | ||
| Pesky solar flares, temporal distortions, stray forces, heck even the flap of a space butterfly's wing can cause a random bit to flip in transmission. |
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Suggested change
| Pesky solar flares, temporal distortions, stray forces, heck even the flap of a space butterfly's wing can cause a random bit to flip in transmission. | |
| Pesky solar flares, temporal distortions, stray forces, even the flap of a space butterfly's wing can cause a random bit to change during transmission. |
We haven’t introduced what flipping signifies.
IsaacG
reviewed
Mar 8, 2025
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| # Instructions | |||
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| Your job is to help implement the message sequencer to add the parity bit to the messages and the decoder to receive messages. | |||
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The double "to" in this sentence might be worth changing.
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| The first group contains two 1s (an even number of 1s), so 0 is appended to the group. | ||
| The second group has none, so append 0. | ||
| The rest have three, so they append 1. |
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Drop the "they". There is no "them" in the other steps.
| | C 0 | 0 0 | 7 1 | 1 B | E 1 | (in hex) | ||
| ``` | ||
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| Thus, the transmission sequence is 0xC0_00_71_1B_E1. |
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Suggested change
| Thus, the transmission sequence is 0xC0_00_71_1B_E1. | |
| The resulting transmission sequence is `0xC0_00_71_1B_E1`. |
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| Trillions upon trillions of messages zip between Earth and neighboring galaxies every millisecond. | ||
| But transmitting over such long distances is tricky. | ||
| Pesky solar flares, temporal distortions, stray forces, heck even the flap of a space butterfly's wing can cause a random bit to flip in transmission. |
There was a problem hiding this comment.
Suggested change
| Pesky solar flares, temporal distortions, stray forces, heck even the flap of a space butterfly's wing can cause a random bit to flip in transmission. | |
| Pesky solar flares, temporal distortions, stray forces, and even the flap of a space butterfly's wing can cause a random bit to flip in transmission. |
| - Losing contact with the Kepler Whirl system when "save new worm hole" becomes "cave new worm hole". | ||
| - Or plunging the universe into existential horror by replacing a cowboy emoji 🤠 with a clown emoji 🤡. | ||
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| Thus, detecting corrupted messages isn’t just important — it’s critical. |
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| Thus, detecting corrupted messages isn’t just important — it’s critical. | |
| Detecting corrupted messages isn’t just important — it’s critical. |
| But how? | ||
| Scientists and engineers from across the universe have been battling this problem for eons. | ||
| Entire cosmic AI superclusters churn through the data. | ||
| And then, one day, a legend resurfaces - an ancient, powerful method, whispered in debugging forums, muttered by engineers who've seen too much ... |
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Suggested change
| And then, one day, a legend resurfaces - an ancient, powerful method, whispered in debugging forums, muttered by engineers who've seen too much ... | |
| And then, one day, a legend resurfaces - an ancient, powerful method, whispered in debugging forums, muttered by engineers who've seen too much... |
| Entire cosmic AI superclusters churn through the data. | ||
| And then, one day, a legend resurfaces - an ancient, powerful method, whispered in debugging forums, muttered by engineers who've seen too much ... | ||
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| The Parity Bit. |
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Suggested change
| The Parity Bit. | |
| The Parity Bit! |
| title = "Intergalactic Transmission" | ||
| blurb = "Add parity bits to a message for transmission" | ||
| source = "Kah Goh" | ||
| source_url = "" |
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This is a proposal for a parity bit exercise.
I've created a proof of concept: exercism/csharp#2398
Note, I wasn't quite sure how best to represent byte data in the JSON. I've used an array of strings with the hex values as Visual Code was telling me "expected comma" if I didn't use the string.