Inspired by a riddle for 2015, I'm interested in the problem of representing the number 2017 using the numbers $$ 1 \quad 2 \quad 3 \quad 4 \quad 5 \quad 6 \quad 7 \quad 8 \quad 9 $$ writtend down in this order, and the basic arithmetic operations $+, - \times, \div$, as well as parentheses.
It is fairly easy to find a such solution, such as: $$ - 1 + 2 + (3 × (4 + 5) − 6 + 7) × 8 × 9 = 2017 $$
How many such solutions exist? What is the simplest one (with reference to some reasonable notion of complexity)?
i found this: $$1+(-2+3+4+5-6)\cdot7\cdot8\cdot9=2017$$