0165.go

// Source: https://leetcode.com/problems/compare-version-numbers
// Title: Compare Version Numbers
// Difficulty: Medium
// Author: Mu Yang <http://muyang.pro>

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Given two version strings, version1 and version2, compare them. A version string consists of revisions separated by dots '.'. The value of the revision is its integer conversion ignoring leading zeros.
// To compare version strings, compare their revision values in left-to-right order. If one of the version strings has fewer revisions, treat the missing revision values as 0.
//
// Return the following:
//   * If version1 < version2, return -1.
//   * If version1 > version2, return 1.
//   * Otherwise, return 0.
//
// Example 1:
//
//   Input: version1 = "1.2", version2 = "1.10"
//   Output: -1
//   Explanation: version1's second revision is "2" and version2's second revision is "10": 2 < 10, so version1 < version2.
//
// Example 2:
//
//   Input: version1 = "1.01", version2 = "1.001"
//   Output: 0
//   Explanation: Ignoring leading zeroes, both "01" and "001" represent the same integer "1".
//
// Example 3:
//
//   Input: version1 = "1.0", version2 = "1.0.0.0"
//   Output: 0
//   Explanation: version1 has less revisions, which means every missing revision are treated as "0".
//
// 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.
//
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

package main

import (
	"strconv"
	"strings"
)

func compareVersion(version1 string, version2 string) int {
	ver1 := strings.Split(version1, ".")
	ver2 := strings.Split(version2, ".")

	l1, l2 := len(ver1), len(ver2)
	n := max(l1, l2)

	for i := 0; i < n; i++ {
		v1, v2 := 0, 0
		if i < l1 {
			v1, _ = strconv.Atoi(ver1[i])
		}
		if i < l2 {
			v2, _ = strconv.Atoi(ver2[i])
		}

		if v1 < v2 {
			return -1
		}
		if v1 > v2 {
			return 1
		}
	}

	return 0
}