diff --git a/data_compression/delta_encoding.py b/data_compression/delta_encoding.py new file mode 100644 index 000000000000..1172a7882835 --- /dev/null +++ b/data_compression/delta_encoding.py @@ -0,0 +1,77 @@ +""" +Delta Encoding +-------------- + +Delta encoding is a lossless data compression method that stores the difference +(delta) between sequential values instead of the absolute values themselves. + +For example: + Input: [100, 103, 105, 108] + Output: [100, 3, 2, 3] + +The first element is stored as-is; each subsequent value is replaced +by the difference from its predecessor. + +This is useful for compressing data that changes gradually, such as +sensor readings, time series data, or pixel values in images. + +Reference: +https://en.wikipedia.org/wiki/Delta_encoding +""" + + +def delta_encode(data: list[int]) -> list[int]: + """ + Encodes a list of integers using delta encoding. + + Args: + data (list[int]): A list of integers. + + Returns: + list[int]: Delta-encoded list. + + Example: + >>> delta_encode([100, 103, 105, 108]) + [100, 3, 2, 3] + """ + if not data: + return [] + + deltas = [data[0]] + for i in range(1, len(data)): + deltas.append(data[i] - data[i - 1]) + return deltas + + +def delta_decode(encoded: list[int]) -> list[int]: + """ + Decodes a delta-encoded list back to the original sequence. + + Args: + encoded (list[int]): Delta-encoded list. + + Returns: + list[int]: Decoded list of integers. + + Example: + >>> delta_decode([100, 3, 2, 3]) + [100, 103, 105, 108] + """ + if not encoded: + return [] + + decoded = [encoded[0]] + for i in range(1, len(encoded)): + decoded.append(decoded[-1] + encoded[i]) + return decoded + + +if __name__ == "__main__": + # Example run + data = [100, 103, 105, 108] + encoded = delta_encode(data) + decoded = delta_decode(encoded) + + print(f"Original data: {data}") + print(f"Delta Encoded: {encoded}") + print(f"Delta Decoded: {decoded}")