栈·bracket 模式

识别信号

• Do you handle mismatched closing brackets without scanning the entire string?
• Can you explain why using counts alone does not guarantee validity in nested brackets?

解题流程

1. 1. 明确窗口/状态定义
2. 2. 更新状态并维护约束
3. 3. 用边界样例验证

常见失分点

• Relying only on counts of brackets, which ignores nesting order and can produce false positives.