Compare Version Numbers
Real-world version: Firmware Revision OrderThe statement here is our own: the same inputs, outputs and technique.
A device reports its firmware revision as a string: one or more chunks of
decimal digits joined by single dots, for example "4.11.0".
A chunk is read as a plain decimal integer, so leading zeros inside a chunk carry
no meaning and "3.04" names the same revision as "3.4".
Compare the revisions left and right. Line their chunks up starting from the
leftmost one. When one revision runs out of chunks before the other, treat each
of its missing chunks as 0.
Return -1 when left is the earlier revision, 1 when right is the earlier
revision, and 0 when the two strings name the same revision.
Examples
Example 1
- Input
- left = "2.9", right = "2.10"
- Output
- -1
The first chunks tie at 2. The second chunks read as 9 and 10, and 9 is the smaller integer, so left is the earlier revision.
Example 2
- Input
- left = "7.012", right = "7.12"
- Output
- 0
The chunk "012" reads as the integer 12, matching "12", and the first chunks both read as 7, so the two strings name the same revision.
Example 3
- Input
- left = "5.0.1", right = "5"
- Output
- 1
Padding the right-hand revision gives chunks 5, 0 and 0. The first two pairs tie and the third pair is 1 against 0, so right is the earlier revision.
Example 4
- Input
- left = "3.0", right = "3"
- Output
- 0
The missing chunk on the right counts as 0, which matches the 0 on the left, so the revisions are the same.
Constraints
- 1 <= left.length, right.length <= 500
- left and right contain only digits and '.'.
- left and right are valid revision strings.
- Every chunk in left and right fits in a 32-bit signed integer.
The signature
The editor starts with this. It matches the parent problem's shape, so a solution that works here works on a standard judge unchanged.
def compare_version(left: str, right: str) -> int:public int compareVersion(String left, String right)Checking your plan…
How this problem was checked
- Passed: Reference solution run against 13 test cases: 13 passed
- Passed: 4 worked examples confirmed by running the code
- Passed: 0 eight-word sequences shared with the parent problem's text
- Passed: Agrees with an independent brute-force solution on random inputs
- Passed: Test set shown to catch deliberately broken solutions
- Passed: Reviewed by a separate quality pass
- Passed: Function arity matches the parent problem's