- محدودیت زمان: ۱ ثانیه
- محدودیت حافظه: ۲۵۶ مگابایت
Mahsa has been practicing shuffling cards for a few months now. Tonight, she finally decided to invite her friends over and show off her new skills. So she picks up a deck with $2n$ cards, shows her friends the face of the cards without changing the deck order and asks someone to pick two positions $i$ and $j$ in the deck. Then, she tells everyone that she is going to move the card in the $i$-th position to the $j$-th position by applying only two types of shuffles.
Assume the cards in the deck are $\langle c_1, c_2, \dots, c_{2n} \rangle$. Mahsa can perform these two shuffles as many times as she wants:
Riffle: Divide the cards into two parts $\langle c_1, \dots, c_n \rangle$ and $\langle c_{n+1}, \dots, c_{2n} \rangle$ and produce $\langle c_1, c_{n+1}, c_2, c_{n+2}, \dots, c_n, c_{2n} \rangle$.
Scuffle: From $\langle c_1, c_2, \dots, c_{2n} \rangle$, produce $\langle c_2, c_1, c_4, c_3, \dots, c_{2n}, c_{2n-1} \rangle$.
Help Mahsa find out the minimum number of shuffles she needs, and she’ll figure out the rest.
ورودی
The input consists of a single line containing three space-separated integers $n$, $i$ and $j$ ($1 \leq n \leq 10^5$ and $1 \leq i, j \leq 2n$).
خروجی
Print a single integer, the minimum number of shuffles required to bring the $i$-th card to the $j$-th position. If it is not possible to do so, print $-1$ instead.
مثالها
ورودی نمونه ۱
4 3 8
خروجی نمونه ۱
3
ورودی نمونه ۲
5 4 1
خروجی نمونه ۲
5
ورودی نمونه ۳
1 1 1
خروجی نمونه ۳
0
ارسال پاسخ برای این سؤال