feat: resolve examples but a submission failed

Author: jtr109

generate_parentheses/src/lib.rs

@@ -1,24 +1,57 @@
 pub struct Solution {}
 
 impl Solution {
-    pub fn generate_parenthesis(n: i32) -> Vec<String> {}
+    pub fn generate_parenthesis(n: i32) -> Vec<String> {
+        if n == 1 {
+            return vec!["()".to_string()];
+        }
+        let mut result = Vec::new();
+        for r in Self::generate_parenthesis(n - 1) {
+            result.push(format!("({})", r));
+            let s1 = format!("(){}", r);
+            let s2 = format!("{}()", r);
+            if s2 != s1 {
+                result.push(s2);
+            }
+            result.push(s1);
+        }
+        result
+    }
 }
 
 #[cfg(test)]
 mod tests {
     use super::*;
 
+    fn it_works(n: i32, expected: Vec<&str>) {
+        let mut result = Solution::generate_parenthesis(n);
+        let mut exp = expected.to_vec();
+        result.sort();
+        exp.sort();
+        assert_eq!(result, exp);
+    }
+
     #[test]
     fn example_1() {
         let n = 3;
         let expected = ["((()))", "(()())", "(())()", "()(())", "()()()"];
-        assert_eq!(Solution::generate_parenthesis(n), expected.to_vec());
+        it_works(n, expected.to_vec());
     }
 
     #[test]
     fn example_2() {
         let n = 1;
         let expected = ["()"];
-        assert_eq!(Solution::generate_parenthesis(n), expected.to_vec());
+        it_works(n, expected.to_vec());
+    }
+
+    #[test]
+    fn submission_1() {
+        let n = 4;
+        let expected = [
+            "(((())))", "((()()))", "((())())", "((()))()", "(()(()))", "(()()())", "(()())()",
+            "(())(())", "(())()()", "()((()))", "()(()())", "()(())()", "()()(())", "()()()()",
+        ];
+        it_works(n, expected.to_vec());
     }
 }