22. Generate Parentheses

Author: papilo-cloud

Backtracking/generate_parenthesis.py

@@ -0,0 +1,32 @@
+# Given n pairs of parentheses, write a function to generate all combinations of 
+# well-formed parentheses.
+
+
+# Example 1:
+# Input: n = 3
+# Output: ["((()))","(()())","(())()","()(())","()()()"]
+
+# Example 2:
+# Input: n = 1
+# Output: ["()"]
+ 
+# Constraints:
+# 1 <= n <= 8
+
+
+class Solution:
+    def generateParenthesis(self, n: int) -> list[str]:
+        res = []
+        def recurs(l, r, s:list[str]):
+            if l == 0 and r == 0:
+                res.append(''.join(s))
+            if l > 0:
+                s.append('(')
+                recurs(l-1, r, s)
+                s.pop()
+            if l < r:
+                s.append(')')
+                recurs(l, r-1, s)
+                s.pop()
+        recurs(n, n, [])
+        return res