問題

Given two version numbers, version1 and version2, compare them.

Version numbers consist of one or more revisions joined by a dot '.'. Each revision consists of digits and may contain leading zeros. Every revision contains at least one character. Revisions are 0-indexed from left to right, with the leftmost revision being revision 0, the next revision being revision 1, and so on. For example 2.5.33 and 0.1 are valid version numbers.

To compare version numbers, compare their revisions in left-to-right order. Revisions are compared using their integer value ignoring any leading zeros. This means that revisions 1 and 001 are considered equal. If a version number does not specify a revision at an index, then treat the revision as 0. For example, version 1.0 is less than version 1.1 because their revision 0s are the same, but their revision 1s are 0 and 1 respectively, and 0 < 1.

Return the following:

If version1 < version2, return -1.
If version1 > version2, return 1.
Otherwise, return 0.

Example 1:

Input: version1 = "1.01", version2 = "1.001"
Output: 0
Explanation: Ignoring leading zeroes, both "01" and "001" represent the same integer "1".

Example 2:

Input: version1 = "1.0", version2 = "1.0.0"
Output: 0
Explanation: version1 does not specify revision 2, which means it is treated as "0".

Example 3:

Input: version1 = "0.1", version2 = "1.1"
Output: -1
Explanation: version1's revision 0 is "0", while version2's revision 0 is "1". 0 < 1, so version1 < version2.

Constraints:

1 <= version1.length, version2.length <= 500
version1 and version2 only contain digits and '.'.
version1 and version2 are valid version numbers.
All the given revisions in version1 and version2 can be stored in a 32-bit integer.

提示

split and join

Python

txt = "1.20.0.1"
arr = txt.split(".") # ['1', '20', '0', '1']
txt2 = '-'.join(arr) # 1-20-0-1

Go

import "string"

txt := "1.20.0.1"
arr := strings.Split(txt, ".")
txt2 := strings.Join(str, "-")

Convert string to integer type

Python

intVar = int("100")

go

Go 必須使用 strconv 套件蔥的 Atoi() 函式來把 String 轉換成 Integer
直接用 int("100") 會報錯 cannot convert "100" (type untyped string) to type int．

import (
	"fmt"
	"strconv"
)

func main() {
	strVar := "100"
	intVar, err := strconv.Atoi(strVar)
	fmt.Println(intVar, err)
}

我的答案

將字串 Split 成陣列，再一一比對每個 subVersion 的數值大小
注意為了比對兩個不同長度的陣列，我們必須先把較短的陣列插入值0，直到兩個陣列長度一致．

Python

Python 可用 套件中的 zip_longest 函式

from itertools import zip_longest
class Solution:
    def compareVersion(self, version1: str, version2: str) -> int:
        v1 = [int(n) for n in version1.split('.')]
        v2 = [int(n) for n in version2.split('.')]
        
        for sv1, sv2 in zip_longest(v1, v2, fillvalue=0):
            if sv1 < sv2:
                return -1
            elif sv1 > sv2:
                return 1
        return 0

Go

Go 沒有 itertools 套件可以用,必須自己手動把較短的陣列插入值0．

import (
    "strings"
    "strconv"
)

func compareVersion(version1 string, version2 string) int {
    v1 := strings.Split(version1, ".")
    v2 := strings.Split(version2, ".")

    // fill shorter array
    n1 := len(v1)
    n2 := len(v2)
    if n1 < n2 {
        for i := 0; i < n2-n1; i++ {
            v1 = append(v1, "0")
        }
    } else {
        for i := 0; i < n1-n2; i++ {
            v2 = append(v2, "0")
        }
    }


    // Compare each subVersion
    for i := 0; i < len(v1); i++ {
        sv1, _ := strconv.Atoi(v1[i])
        sv2, _ := strconv.Atoi(v2[i])
        if sv1 < sv2 {
            return -1
        } else if sv1 > sv2 {
            return 1
        }
    }
    return 0

}