rs: add «165. Compare Version Numbers»

Signed-off-by: Matej Focko <me@mfocko.xyz>

rs/compare-version-numbers.rs

@@ -0,0 +1,30 @@
+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
+    }
+}