init

2023/day9/p2/main.py

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+INPUT_FILE = "input.text"
+
+def extrapolate_value(line: str) -> int:
+
+    initial_values: list[int] = [int(v) for v in line.split(' ')]
+
+    values = [initial_values]
+
+    # Loop until last thing is all 0, 0, 0...
+    while len(values[-1]) != values[-1].count(0):
+        new_values: list[int] = []
+
+        current_row: list[int] = values[-1]
+        for value_index in range(1, len(current_row)):
+            new_values.append(current_row[value_index] - current_row[value_index - 1])
+
+        values.append(new_values)
+
+    # Now we can extrapolate our new values, starting from the bottom
+    for row_index in reversed(range(0, len(values) - 2)): # -1 because we know the last row is all 0's
+        current_row: list[int] = values[row_index]
+        row_bellow: list[int] = values[row_index + 1]
+
+        values[row_index].insert(0, current_row[0] - row_bellow[0])
+
+    return values[0][0] # Return last value of the first row
+
+
+def main():
+
+    with open(INPUT_FILE, 'r') as file:
+        lines = file.readlines()
+
+    sum_of_values = 0
+    for line in lines:
+        extrapolated_history_value: int = extrapolate_value(line)
+
+        sum_of_values += extrapolated_history_value
+
+    print(f'Sum of extrapolated values: {sum_of_values}')
+
+
+
+
+if __name__ == "__main__":
+    main()
+
+
+