1624. Largest Substring Between Two Equal Characters: AC

Author: tan-wei

src/solution/mod.rs

@@ -1224,3 +1224,4 @@ mod s1619_mean_of_array_after_removing_some_elements;
 mod s1620_coordinate_with_maximum_network_quality;
 mod s1621_number_of_sets_of_k_non_overlapping_line_segments;
 mod s1622_fancy_sequence;
+mod s1624_largest_substring_between_two_equal_characters;

src/solution/s1624_largest_substring_between_two_equal_characters.rs

@@ -0,0 +1,87 @@
+/**
+ * [1624] Largest Substring Between Two Equal Characters
+ *
+ * Given a string s, return the length of the longest substring between two equal characters, excluding the two characters. If there is no such substring return -1.
+ * A substring is a contiguous sequence of characters within a string.
+ *  
+ * Example 1:
+ *
+ * Input: s = "aa"
+ * Output: 0
+ * Explanation: The optimal substring here is an empty substring between the two 'a's.
+ * Example 2:
+ *
+ * Input: s = "abca"
+ * Output: 2
+ * Explanation: The optimal substring here is "bc".
+ *
+ * Example 3:
+ *
+ * Input: s = "cbzxy"
+ * Output: -1
+ * Explanation: There are no characters that appear twice in s.
+ *
+ *  
+ * Constraints:
+ *
+ * 	1 <= s.length <= 300
+ * 	s contains only lowercase English letters.
+ *
+ */
+pub struct Solution {}
+
+// problem: https://leetcode.com/problems/largest-substring-between-two-equal-characters/
+// discuss: https://leetcode.com/problems/largest-substring-between-two-equal-characters/discuss/?currentPage=1&orderBy=most_votes&query=
+
+// submission codes start here
+
+impl Solution {
+    pub fn max_length_between_equal_characters(s: String) -> i32 {
+        s.as_bytes()
+            .into_iter()
+            .enumerate()
+            .fold(vec![vec![]; 26], |mut v, (ind, c)| {
+                v[(c - b'a') as usize].push(ind as i32);
+                v
+            })
+            .into_iter()
+            .filter(|indexes| !indexes.is_empty())
+            .map(|indexes| indexes.last().unwrap() - indexes.first().unwrap() - 1)
+            .max()
+            .unwrap_or(-1)
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_1624_example_1() {
+        let s = "aa".to_string();
+
+        let result = 0;
+
+        assert_eq!(Solution::max_length_between_equal_characters(s), result);
+    }
+
+    #[test]
+    fn test_1624_example_2() {
+        let s = "abca".to_string();
+
+        let result = 2;
+
+        assert_eq!(Solution::max_length_between_equal_characters(s), result);
+    }
+
+    #[test]
+    fn test_1624_example_2() {
+        let s = "cbzxy".to_string();
+
+        let result = -1;
+
+        assert_eq!(Solution::max_length_between_equal_characters(s), result);
+    }
+}