Add num_unique_emails

Author: martwz

README.md

@@ -32,6 +32,7 @@ LeetCode is a website that has programming-related questions that are designed t
 | 713 | Subarray Product Less Than K | [Rust](https://github.com/martinxxd/leetcode-rust/tree/master/./src/leetcode/problem/num_subarray_product_less_than_k.rs) | [Leetcode](https://leetcode.com/problems/subarray-product-less-than-k/) | Medium |
 | 774 | Minimize Max Distance to Gas Station | [Rust](https://github.com/martinxxd/leetcode-rust/tree/master/./src/leetcode/challenge/minmax_gas_dist.rs) | [Leetcode](https://leetcode.com/problems/minimize-max-distance-to-gas-station/) | Medium |
 | 875 | Koko Eating Bananas | [Rust](https://github.com/martinxxd/leetcode-rust/tree/master/./src/leetcode/problem/min_eating_speed.rs) | [Leetcode](https://leetcode.com/problems/koko-eating-bananas/) | Medium |
+| 929 | Unique Email Addresses | [Rust](https://github.com/martinxxd/leetcode-rust/tree/master/./src/leetcode/challenge/num_unique_emails.rs) | [Leetcode](https://leetcode.com/problems/unique-email-addresses/) | Easy |
 | 1035 | Uncrossed Lines | [Rust](https://github.com/martinxxd/leetcode-rust/tree/master/./src/leetcode/problem/max_uncrossed_lines.rs) | [Leetcode](https://leetcode.com/problems/uncrossed-lines/) | Medium |
 | 1134 | Armstrong Number | [Rust](https://github.com/martinxxd/leetcode-rust/tree/master/./src/leetcode/problem/is_good_array.rs) | [Leetcode](https://leetcode.com/problems/armstrong-number/) | Easy |
 | 1137 | N-th Tribonacci Number | [Rust](https://github.com/martinxxd/leetcode-rust/tree/master/./src/leetcode/challenge/tribonacci.rs) | [Leetcode](https://leetcode.com/problems/n-th-tribonacci-number/) | Easy |

src/leetcode/challenge/mod.rs

@@ -5,6 +5,7 @@ mod max_length;
 mod minmax_gas_dist;
 mod moves_to_chessboard;
 mod num_distinct;
+mod num_unique_emails;
 mod shortest_distance;
 mod shortest_path;
 mod spiral_order;

src/leetcode/challenge/num_unique_emails.rs

@@ -0,0 +1,58 @@
+use std::collections::HashSet;
+
+// 929. Unique Email Addresses, Easy
+// https://leetcode.com/problems/unique-email-addresses/
+impl Solution {
+    pub fn num_unique_emails(emails: Vec<String>) -> i32 {
+        let mut set = HashSet::new();
+
+        for email in emails {
+            let email: Vec<_> = email.split('@').collect();
+            let mut vhost: String = email[0].to_string().replace(".", "");
+            if vhost.contains("+") {
+                vhost = vhost.split('+').next().unwrap().to_string();
+            }
+
+            let domain: String = email[1].to_string();
+
+            set.insert(format!("{}@{}", vhost, domain));
+        }
+
+        return set.len() as i32;
+    }
+}
+
+struct Solution {}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::vec_string;
+
+    #[test]
+    fn test_num_unique_emails() {
+        assert_eq!(
+            Solution::num_unique_emails(vec_string![
+                "test.email+alex@leetcode.com",
+                "test.e.mail+bob.cathy@leetcode.com",
+                "testemail+david@lee.tcode.com"
+            ]),
+            2
+        );
+    }
+
+    #[test]
+    fn test_num_unique_emails2() {
+        assert_eq!(Solution::num_unique_emails(vec_string!["a@leetcode.com", "b@leetcode.com", "c@leetcode.com"]), 3);
+    }
+
+    #[test]
+    fn test_num_unique_emails3() {
+        assert_eq!(Solution::num_unique_emails(vec_string!["a@leetcode.com", "a@leetcode.com"]), 1);
+    }
+
+    #[test]
+    fn test_num_unique_emails4() {
+        assert_eq!(Solution::num_unique_emails(vec_string![]), 0);
+    }
+}