thecoded.prof
CMU Coding Bootcamp
feat: oct 2 level 4+
additional solution for route cipher
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+66
python/oct2/level4/routeCipher2.py
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python/oct2/level4/routeCipher2.py
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from math import ceil
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def f(row: int, col: int, rows: int) -> int:
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return col*rows + row
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def i_f(x: int, rows: int) -> tuple[int, int]:
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return x // rows, x % rows
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def encodeRouteCipher(message: str, rows: int) -> str:
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cur_char = "z"
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row_len = ceil(len(message) / rows)
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while len(message) % rows != 0:
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message += cur_char
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cur_char = chr(ord(cur_char) - 1)
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encoded_string = ""
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for i in range(len(message)):
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row, col = i_f(i, row_len)
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encoded_string += message[f(row, col, rows)]
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encoded_message = f"{rows}"
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for i in range(0, rows):
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if i % 2 == 0:
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encoded_message += encoded_string[i*row_len:(i+1)*row_len]
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else:
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encoded_message += encoded_string[i*row_len:(i+1)*row_len][::-1]
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return encoded_message
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def decodeRouteCipher(encodedMessage: str) -> str:
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decoded_message = ""
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rows = int(encodedMessage[0])
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encoded_string = encodedMessage[1:]
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row_len = ceil(len(encoded_string) / rows)
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decoded_string = ""
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for i in range(rows):
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if i % 2 == 0:
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decoded_string += encoded_string[i*row_len:(i+1)*row_len]
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else:
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decoded_string += encoded_string[i*row_len:(i+1)*row_len][::-1]
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for i in range(len(decoded_string)):
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row, col = i_f(i, rows)
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decoded_message += decoded_string[f(row, col, row_len)]
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while decoded_message[-1].islower():
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decoded_message = decoded_message[:-1]
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return decoded_message
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print("Testing encodeRouteCipher()...", end="")
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assert encodeRouteCipher("ASECRETMESSAGE", 4) == "4AREGESESETSzyAMC"
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assert encodeRouteCipher("ASECRETMESSAGE", 3) == "3ACTSGESMRSEEEAz"
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assert encodeRouteCipher("ASECRETMESSAGE", 5) == "5AESATSEMGEECRSz"
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assert encodeRouteCipher("ANOTHERSECRET", 4) == "4AHETzCENORRyxEST"
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print("Testing decodeRouteCipher()...", end="")
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assert decodeRouteCipher("4AREGESESETSzyAMC") == "ASECRETMESSAGE"
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assert decodeRouteCipher("3ACTSGESMRSEEEAz") == "ASECRETMESSAGE"
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assert decodeRouteCipher("5AESATSEMGEECRSz") == "ASECRETMESSAGE"
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assert decodeRouteCipher("4AHETzCENORRyxEST") == "ANOTHERSECRET"
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message = "SECRETSTUFFGOESHERE"
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encodedMessage = encodeRouteCipher(message, 6)
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plaintext = decodeRouteCipher(encodedMessage)
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assert plaintext == message
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print("Passed!")