Create 1106-ParsingABooleanExpression.py

Author: Jiezhi

src/1106-ParsingABooleanExpression.py

@@ -0,0 +1,84 @@
+#!/usr/bin/env python3
+"""
+CREATED AT: 2022-11-05
+
+URL: https://leetcode.com/problems/parsing-a-boolean-expression/
+
+GITHUB: https://github.com/Jiezhi/myleetcode
+
+FileName: 1106-ParsingABooleanExpression
+
+Difficulty: Hard
+
+Desc: 
+
+Tag: 
+
+See: 
+
+"""
+
+
+class Solution:
+    def parseBoolExpr(self, expression: str) -> bool:
+        """
+        Runtime: 85 ms, faster than 73.11%
+        Memory Usage: 14.1 MB, less than 61.79%
+
+        1 <= expression.length <= 2 * 104
+        expression[i] is one following characters: '(', ')', '&', '|', '!', 't', 'f', and ','.
+        """
+        if expression == 't':
+            return True
+        if expression == 'f':
+            return False
+        sub = expression[2:-1]
+        if expression[0] == '!':
+            return not self.parseBoolExpr(sub)
+        elif expression[0] == '|':
+            left = 0
+            cur = 0
+            for i, c in enumerate(sub):
+                if c == '(':
+                    if left == 0:
+                        cur = i - 1
+                    left += 1
+                elif c == ')':
+                    left -= 1
+                    if left == 0:
+                        if self.parseBoolExpr(sub[cur:i + 1]):
+                            return True
+                        else:
+                            cur = i + 2
+                elif left == 0 and c == 't':
+                    return True
+            return False
+        elif expression[0] == '&':
+            left = 0
+            cur = 0
+            for i, c in enumerate(sub):
+                if c == '(':
+                    if left == 0:
+                        cur = i - 1
+                    left += 1
+                elif c == ')':
+                    left -= 1
+                    if left == 0:
+                        if not self.parseBoolExpr(sub[cur:i + 1]):
+                            return False
+                        else:
+                            cur = i + 2
+                elif left == 0 and c == 'f':
+                    return False
+            return True
+
+
+def test():
+    assert Solution().parseBoolExpr(expression="|(f,f,f,!(f))")
+    assert not Solution().parseBoolExpr(expression="&(|(f))")
+    assert Solution().parseBoolExpr(expression="|(f,f,f,t)")
+    assert Solution().parseBoolExpr(expression="!(&(f,t))")
+
+
+if __name__ == '__main__':
+    test()