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#!/usr/bin/env python3
from itertools import product, zip_longest
import re
import sys
def magic_expression(input_string: str | int, target: int) -> list[str]:
"""Return all expressions formed by inserting +, -, * between digits
of input_string that evaluate to target.
Args:
input_string (str | int): A string or integer consisting of digits.
target (int): The target integer value.
Returns:
list[str]: A list of expressions that evaluate to target.
"""
# Turn input into a string if it isn't already
input_string = str(input_string)
if not re.search(r'^[0-9]+$', input_string):
raise ValueError("Input string must contain only digits")
# Possible operators to insert between digits
operators = ['', '+', '-', '*']
magic_expressions = []
for ops in product(operators, repeat=len(input_string)-1):
expression = ''.join(
digit + op for digit, op in zip_longest(input_string, ops, fillvalue='')
)
if re.search(r'[\+\-\*]0\d', expression):
# Skip expressions with leading zeros
continue
if eval(expression) == target:
magic_expressions.append(expression)
return magic_expressions
def main():
result = magic_expression(sys.argv[1], int(sys.argv[2]))
if not result:
print("No expressions found")
else:
print('("' + '", "'.join(result) + '")')
if __name__ == '__main__':
main()
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