Recursion - medium - generate balanced parentheses implementation

Author: rajithst

recursion/medium/generate_parantheses.py

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+from typing import List
+
+
+class TreeInfo:
+    def __init__(self):
+        self.results = []
+
+
+class Solution:
+    def generateParenthesis(self, n: int) -> List[str]:
+
+        # if n == 3,we can fill 6 positions
+        # we have two conditions
+        # 1) if opened parenthesis count is less than N
+        #       if true -> we can add another open parenthesis
+        # 2) if closed parenthesis less than open parenthesis
+        #       if true -> we can add close parenthesis
+        # if total open+closed parenthesis == 2*n means we hit the base case
+        # we found a balanced parenthesis set,add to result
+        def generate(output, n, open_c, close_c, current, ti):
+            if current == n * 2:
+                ti.results.append(output)
+                return
+
+            if open_c < n:
+                generate(output + "(", n, open_c + 1, close_c, current + 1, ti)
+
+            if close_c < open_c:
+                generate(output + ")", n, open_c, close_c + 1, current + 1, ti)
+
+        ti = TreeInfo()
+        generate("", n, 0, 0, 0, ti)
+        return ti.results