Add problem 2744: Find Maximum Number of String Pairs

Author: EFanZh

src/lib.rs

@@ -1957,6 +1957,7 @@ pub mod problem_2733_neither_minimum_nor_maximum;
 pub mod problem_2734_lexicographically_smallest_string_after_substring_operation;
 pub mod problem_2739_total_distance_traveled;
 pub mod problem_2740_find_the_value_of_the_partition;
+pub mod problem_2744_find_maximum_number_of_string_pairs;
 
 #[cfg(test)]
 mod test_utilities;

src/problem_2744_find_maximum_number_of_string_pairs/hash_set.rs

@@ -0,0 +1,41 @@
+pub struct Solution;
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+use std::collections::HashSet;
+
+impl Solution {
+    pub fn maximum_number_of_string_pairs(words: Vec<String>) -> i32 {
+        let mut reversed = HashSet::new();
+        let mut result = 0;
+
+        for word in words {
+            let mut word = word.into_bytes();
+
+            if reversed.remove(word.as_slice()) {
+                result += 1;
+            } else {
+                word.reverse();
+                reversed.insert(word);
+            }
+        }
+
+        result
+    }
+}
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl super::Solution for Solution {
+    fn maximum_number_of_string_pairs(words: Vec<String>) -> i32 {
+        Self::maximum_number_of_string_pairs(words)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_solution() {
+        super::super::tests::run::<super::Solution>();
+    }
+}

src/problem_2744_find_maximum_number_of_string_pairs/mod.rs

@@ -0,0 +1,25 @@
+pub mod hash_set;
+
+pub trait Solution {
+    fn maximum_number_of_string_pairs(words: Vec<String>) -> i32;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+
+    pub fn run<S: Solution>() {
+        let test_cases = [
+            (&["cd", "ac", "dc", "ca", "zz"] as &[_], 2),
+            (&["ab", "ba", "cc"], 1),
+            (&["aa", "ab"], 0),
+        ];
+
+        for (words, expected) in test_cases {
+            assert_eq!(
+                S::maximum_number_of_string_pairs(words.iter().copied().map(str::to_string).collect()),
+                expected,
+            );
+        }
+    }
+}