20. Valid Parentheses

解題說明

C++ 解法

複雜度分析

虛擬碼

1. Initialize empty stack
2. For each char c in s:
   a. If c is opening bracket: push c
   b. Else (closing bracket):
      - If stack empty: return false
      - If top doesn't match: return false
      - Pop from stack
3. Return stack.empty()

其他解法

延伸思考