201230: [AtCoder]ARC123 A - Arithmetic Sequence
Memory Limit:1024 MB
Time Limit:2 S
Judge Style:Text Compare
Creator:
Submit:0
Solved:0
Description
Score : $300$ points
Problem Statement
Given is a sequence of three integers $A = (A_1, A_2, A_3)$. On this sequence, you can do the following operation any number of times:
- choose $i\in \{1,2,3\}$ and add $1$ to $A_i$.
Find the minimum number of operations needed to make $A$ arithmetic. Here, the sequence $A = (A_1, A_2, A_3)$ is arithmetic when $A_2 - A_1 = A_3 - A_2$ holds.
Constraints
- $1\leq A_1, A_2, A_3\leq 10^{15}$
Input
Input is given from Standard Input in the following format:
$A_1$ $A_2$ $A_3$
Output
Print the answer.
Sample Input 1
4 8 10
Sample Output 1
2
One operation with $i = 1$ and then one operation with $i = 3$ yield an arithmetic sequence $(5, 8, 11)$.
Sample Input 2
10 3 4
Sample Output 2
4
Four operations with $i = 2$ yield an arithmetic sequence $(10, 7, 4)$.
Sample Input 3
1 2 3
Sample Output 3
0
The sequence $A$ is already arithmetic from the beginning, so we need zero operations.
Sample Input 4
1000000000000000 1 1000000000000000
Sample Output 4
999999999999999