impl summary ranges

leetcode-rs/src/solutions/summary_ranges.rs

@@ -1,3 +1,5 @@
+use std::ops::Range;
+
 use super::{test_helper, Solution};
 
 pub struct SolutionImpl;
@@ -16,6 +18,34 @@ crate::derive_solution!(
 
 impl SolutionImpl {
     pub fn summary_ranges(nums: Vec<i32>) -> Vec<String> {
-        todo!()
+        if nums.is_empty() {
+            return vec![];
+        }
+        let mut ranges: Vec<Range<i32>> = Vec::new();
+        let mut start = nums[0];
+        let mut end = nums[0] + 1;
+
+        for num in nums.into_iter().skip(1) {
+            if num == end {
+                end += 1;
+            } else {
+                ranges.push(start..end);
+                start = num;
+                end = num + 1;
+            }
+        }
+
+        ranges.push(start..end);
+
+        ranges
+            .into_iter()
+            .map(|range| {
+                if range.len() == 1 || range.start == i32::MAX {
+                    format!("{}", range.start)
+                } else {
+                    format!("{}->{}", range.start, range.end - 1)
+                }
+            })
+            .collect()
     }
 }