1750. Minimum Length of String After Deleting Similar Ends

Author: tan-wei

src/solution/mod.rs

@@ -1318,3 +1318,4 @@ mod s1744_can_you_eat_your_favorite_candy_on_your_favorite_day;
 mod s1745_palindrome_partitioning_iv;
 mod s1748_sum_of_unique_elements;
 mod s1749_maximum_absolute_sum_of_any_subarray;
+mod s1750_minimum_length_of_string_after_deleting_similar_ends;

src/solution/s1750_minimum_length_of_string_after_deleting_similar_ends.rs

@@ -0,0 +1,101 @@
+/**
+ * [1750] Minimum Length of String After Deleting Similar Ends
+ *
+ * Given a string s consisting only of characters 'a', 'b', and 'c'. You are asked to apply the following algorithm on the string any number of times:
+ * <ol>
+ * 	Pick a non-empty prefix from the string s where all the characters in the prefix are equal.
+ * 	Pick a non-empty suffix from the string s where all the characters in this suffix are equal.
+ * 	The prefix and the suffix should not intersect at any index.
+ * 	The characters from the prefix and suffix must be the same.
+ * 	Delete both the prefix and the suffix.
+ * </ol>
+ * Return the minimum length of s after performing the above operation any number of times (possibly zero times).
+ *  
+ * Example 1:
+ *
+ * Input: s = "ca"
+ * Output: 2
+ * Explanation: You can't remove any characters, so the string stays as is.
+ *
+ * Example 2:
+ *
+ * Input: s = "cabaabac"
+ * Output: 0
+ * Explanation: An optimal sequence of operations is:
+ * - Take prefix = "c" and suffix = "c" and remove them, s = "abaaba".
+ * - Take prefix = "a" and suffix = "a" and remove them, s = "baab".
+ * - Take prefix = "b" and suffix = "b" and remove them, s = "aa".
+ * - Take prefix = "a" and suffix = "a" and remove them, s = "".
+ * Example 3:
+ *
+ * Input: s = "aabccabba"
+ * Output: 3
+ * Explanation: An optimal sequence of operations is:
+ * - Take prefix = "aa" and suffix = "a" and remove them, s = "bccabb".
+ * - Take prefix = "b" and suffix = "bb" and remove them, s = "cca".
+ *
+ *  
+ * Constraints:
+ *
+ * 	1 <= s.length <= 10^5
+ * 	s only consists of characters 'a', 'b', and 'c'.
+ *
+ */
+pub struct Solution {}
+
+// problem: https://leetcode.com/problems/minimum-length-of-string-after-deleting-similar-ends/
+// discuss: https://leetcode.com/problems/minimum-length-of-string-after-deleting-similar-ends/discuss/?currentPage=1&orderBy=most_votes&query=
+
+// submission codes start here
+
+impl Solution {
+    pub fn minimum_length(s: String) -> i32 {
+        let mut q = s.chars().collect::<std::collections::VecDeque<char>>();
+
+        while q.len() > 1 && q.front() == q.back() {
+            let cur = q[0];
+            while q.front() == Some(&cur) {
+                q.pop_front();
+            }
+            while q.back() == Some(&cur) {
+                q.pop_back();
+            }
+        }
+
+        q.len() as i32
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_1750_example_1() {
+        let s = "ca".to_string();
+
+        let result = 2;
+
+        assert_eq!(Solution::minimum_length(s), result);
+    }
+
+    #[test]
+    fn test_1750_example_2() {
+        let s = "cabaabac".to_string();
+
+        let result = 0;
+
+        assert_eq!(Solution::minimum_length(s), result);
+    }
+
+    #[test]
+    fn test_1750_example_3() {
+        let s = "aabccabba".to_string();
+
+        let result = 3;
+
+        assert_eq!(Solution::minimum_length(s), result);
+    }
+}