Added make the string great solution.

README.md

@@ -111,6 +111,7 @@ other languages.
 - Unique Number of Occurrences (https://leetcode.com/problems/unique-number-of-occurrences)
 - Minimum Common Value (https://leetcode.com/problems/minimum-common-value)
 - Sort by Number of Bits (https://leetcode.com/problems/sort-integers-by-the-number-of-1-bits)
+- Make the String Great (https://leetcode.com/problems/make-the-string-great/)
 
 #### Medium
 

src/leetcode/make_string_great.rs

@@ -0,0 +1,26 @@
+fn make_good(s: String) -> String {
+    let mut result = String::with_capacity(s.len());
+    for char in s.chars() {
+        if !result.is_empty() && (char as u8).abs_diff(result.chars().last().unwrap() as u8) == 32 {
+            result.pop();
+        } else {
+            result.push(char);
+        }
+    }
+    result
+}
+
+#[cfg(test)]
+mod tests {
+    use test_case::test_case;
+
+    use crate::leetcode::make_string_great::make_good;
+
+    #[test_case("leEeetcode", "leetcode")]
+    #[test_case("abBAcC", "")]
+    #[test_case("s", "s")]
+    fn should_produce_length_of_largest_substring_between_duplicates(s: &str, expected: &str) {
+        let actual = make_good(s.to_string());
+        assert_eq!(actual, expected.to_string());
+    }
+}

src/leetcode/mod.rs

@@ -15,6 +15,7 @@ mod largest_number;
 mod largest_odd_number;
 mod lonely_numbers;
 mod longest_subtsring;
+mod make_string_great;
 mod max_substr_between_duplicates;
 mod merge_lists;
 mod minimum_common_value;