PUZZLE #2539: FHSS Frequency Hopping (diff 1)
6 characters transmitted over 20 channels (5 jammed). Each character sent 2 times. LCG seed 5431 governs the hop schedule.
DATA
| Hop Frequencies |
0, 17, 6, 7, 16, 13, 10, 11, 12, 13, 14, 7
|
| Transmissions |
{'hop': 0, 'freq': 0, 'char_idx': 0, 'char': 'A', 'jammed': False}, {'hop': 1, 'freq': 17, 'char_idx': 1, 'char': None, 'jammed': True}, {'hop': 2, 'freq': 6, 'char_idx': 2, 'char': 'C', 'jammed': False}, {'hop': 3, 'freq': 7, 'char_idx': 3, 'char': None, 'jammed': True}, {'hop': 4, 'freq': 16, 'char_idx': 4, 'char': None, 'jammed': True}, {'hop': 5, 'freq': 13, 'char_idx': 5, 'char': 'P', 'jammed': False}, {'hop': 6, 'freq': 10, 'char_idx': 0, 'char': None, 'jammed': True}, {'hop': 7, 'freq': 11, 'char_idx': 1, 'char': 'K', 'jammed': False}, {'hop': 8, 'freq': 12, 'char_idx': 2, 'char': 'C', 'jammed': False}, {'hop': 9, 'freq': 13, 'char_idx': 3, 'char': 'J', 'jammed': False}, {'hop': 10, 'freq': 14, 'char_idx': 4, 'char': None, 'jammed': True}, {'hop': 11, 'freq': 7, 'char_idx': 5, 'char': None, 'jammed': True}
|
| Jammed Channels |
7, 10, 14, 16, 17
|
| N Channels |
20
|
| N Chars |
6
|
| Redundancy |
2
|
| Seed |
5431
|
| Lcg A |
1103515245
|
| Lcg C |
12345
|
| Lcg M |
2147483648
|
| Hint |
LCG: x_i+1 = (a·x_i + c) mod m. Compute hop sequence from seed, find which hops survived jamming. Group surviving letters by char_idx to reconstruct the word.
|
| Answer Format |
lowercase word, no spaces or punctuation
|
author's note: Audited: fhss diff 1
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