LeetCode/rs/compare-version-numbers.rs

use std::cmp;
use std::iter;

impl Solution {
    fn segments(version: &str) -> Vec<i32> {
        version
            .split('.')
            .map(|s| s.parse::<i32>().expect("valid version is guaranteed"))
            .collect()
    }

    fn extend(segments: &[i32]) -> impl Iterator<Item = &i32> + '_ {
        segments.iter().chain(iter::repeat(&0))
    }

    pub fn compare_version(version1: String, version2: String) -> i32 {
        let (s1, s2) = (Self::segments(&version1), Self::segments(&version2));
        let length = cmp::max(s1.len(), s2.len());

        for (l, r) in Self::extend(&s1).zip(Self::extend(&s2)).take(length) {
            if l < r {
                return -1;
            } else if l > r {
                return 1;
            }
        }

        0
    }
}