Added summary ranges solution.

README.md

@@ -174,6 +174,7 @@ programming challenges completed in other languages.
 - [Happy Number](https://leetcode.com/problems/happy-number)
 - [Valid Parentheses](https://leetcode.com/problems/valid-parentheses)
 - [Contains Duplicate II](https://leetcode.com/problems/contains-duplicate-ii)
+- [Summary Ranges](https://leetcode.com/problems/summary-ranges)
 
 #### Medium
 

src/leetcode/mod.rs

@@ -152,6 +152,7 @@ mod str_pairs;
 mod string_compression;
 mod subarray_sum;
 mod sum_root_to_leaf;
+mod summary_ranges;
 mod take_gifts;
 mod take_k_characters;
 mod third_max;

src/leetcode/summary_ranges.rs

@@ -0,0 +1,36 @@
+pub fn summary_ranges(numbers: Vec<i32>) -> Vec<String> {
+    let n = numbers.len();
+    let mut result = Vec::new();
+    let mut i = 0;
+    while i < n {
+        let left = numbers[i];
+        while i < n - 1 && numbers[i] + 1 == numbers[i + 1] {
+            i += 1;
+        }
+        result.push(match left == numbers[i] {
+            true => format!("{}", left),
+            false => format!("{}->{}", left, numbers[i]),
+        });
+        i += 1;
+    }
+    result
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::string_vec;
+
+    use super::*;
+
+    #[test]
+    fn produces_ranges_of_consecutive_integers() {
+        assert_eq!(
+            string_vec!["0->2", "4->5", "7"],
+            summary_ranges(vec![0, 1, 2, 4, 5, 7])
+        );
+        assert_eq!(
+            string_vec!["0", "2->4", "6", "8->9"],
+            summary_ranges(vec![0, 2, 3, 4, 6, 8, 9])
+        )
+    }
+}