Create delta_encoding.py

data_compression/delta_encoding.py

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+"""
+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}")