1.3 KiB
1.3 KiB
Briefcase Lock
A briefcase has a 4-digit rolling-lock. Each digit is a number from 0-9 that can be rolled either forwards or backwards.
Create a function that returns the smallest number of turns it takes to transform the lock from the current combination to the target combination. One turn is equivalent to rolling a number forwards or backwards by one.
To illustrate:
- current-lock: 4089
- target-lock: 5672
What is the minimum number of turns it takes to transform 4089 to 5672?
4 ➞ 5
4 ➞ 5 // Forward Turns: 1 <- Min
4 ➞ 3 ➞ 2 ➞ 1 ➞ 0 ➞ 9 ➞ 8 ➞ 7 ➞ 6 ➞ 5 // Backward Turns: 9
0 ➞ 6
0 ➞ 1 ➞ 2 ➞ 3 ➞ 4 ➞ 5 ➞ 6 // Forward Turns: 6
0 ➞ 9 ➞ 8 ➞ 7 ➞ 6 // Backward Turns: 4 <- Min
8 ➞ 7
8 ➞ 9 ➞ 0 ➞ 1 ➞ 2 ➞ 3 ➞ 4 ➞ 5 ➞ 6 ➞ 7 // Forward Turns: 9
8 ➞ 7 // Backward Turns: 1 <- Min
9 ➞ 2
9 ➞ 0 ➞ 1 ➞ 2 // Forward Turns: 3 <- Min
9 ➞ 8 ➞ 7 ➞ 6 ➞ 5 ➞ 4 ➞ 3 ➞ 2 // Backward Turns: 7
It takes 1 + 4 + 1 + 3 = 9 minimum turns to change the lock from 4089 to 5672.
Example
MinTurns("4089", "5672") ➞ 9
MinTurns("1111", "1100") ➞ 2
MinTurns("2391", "4984") ➞ 10
Notes
- Both locks are in string format.
- A
9rolls forward to0, and a0rolls backwards to a9.