1957. Delete Characters to Make Fancy String: AC

Author: tan-wei

src/solution/mod.rs

@@ -1474,3 +1474,4 @@ mod s1952_three_divisors;
 mod s1953_maximum_number_of_weeks_for_which_you_can_work;
 mod s1954_minimum_garden_perimeter_to_collect_enough_apples;
 mod s1955_count_number_of_special_subsequences;
+mod s1957_delete_characters_to_make_fancy_string;

src/solution/s1957_delete_characters_to_make_fancy_string.rs

@@ -0,0 +1,98 @@
+/**
+ * [1957] Delete Characters to Make Fancy String
+ *
+ * A fancy string is a string where no three consecutive characters are equal.
+ * Given a string s, delete the minimum possible number of characters from s to make it fancy.
+ * Return the final string after the deletion. It can be shown that the answer will always be unique.
+ *  
+ * Example 1:
+ *
+ * Input: s = "le<u>e</u>etcode"
+ * Output: "leetcode"
+ * Explanation:
+ * Remove an 'e' from the first group of 'e's to create "leetcode".
+ * No three consecutive characters are equal, so return "leetcode".
+ *
+ * Example 2:
+ *
+ * Input: s = "<u>a</u>aab<u>aa</u>aa"
+ * Output: "aabaa"
+ * Explanation:
+ * Remove an 'a' from the first group of 'a's to create "aabaaaa".
+ * Remove two 'a's from the second group of 'a's to create "aabaa".
+ * No three consecutive characters are equal, so return "aabaa".
+ *
+ * Example 3:
+ *
+ * Input: s = "aab"
+ * Output: "aab"
+ * Explanation: No three consecutive characters are equal, so return "aab".
+ *
+ *  
+ * Constraints:
+ *
+ * 	1 <= s.length <= 10^5
+ * 	s consists only of lowercase English letters.
+ *
+ */
+pub struct Solution {}
+
+// problem: https://leetcode.com/problems/delete-characters-to-make-fancy-string/
+// discuss: https://leetcode.com/problems/delete-characters-to-make-fancy-string/discuss/?currentPage=1&orderBy=most_votes&query=
+
+// submission codes start here
+
+impl Solution {
+    pub fn make_fancy_string(s: String) -> String {
+        s.chars()
+            .fold(
+                ("".to_string(), 0, ' '),
+                |(mut result, counter, prev_ch), ch| {
+                    if ch == prev_ch {
+                        if counter < 1 {
+                            result.push_str(ch.to_string().as_str());
+                        }
+                        (result, counter + 1, ch)
+                    } else {
+                        result.push_str(ch.to_string().as_str());
+                        (result, 0, ch)
+                    }
+                },
+            )
+            .0
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_1957_example_1() {
+        let s = "leeetcode".to_string();
+
+        let result = "leetcode".to_string();
+
+        assert_eq!(Solution::make_fancy_string(s), result);
+    }
+
+    #[test]
+    fn test_1957_example_2() {
+        let s = "aaabaaaa".to_string();
+
+        let result = "aabaa".to_string();
+
+        assert_eq!(Solution::make_fancy_string(s), result);
+    }
+
+    #[test]
+    fn test_1957_example_3() {
+        let s = "aab".to_string();
+
+        let result = "aab".to_string();
+
+        assert_eq!(Solution::make_fancy_string(s), result);
+    }
+}