maximum number of subsequences after one inserting core interview pattern 模式

识别信号

• The candidate uses precomputation effectively to reduce the complexity of subsequence counting.
• The solution demonstrates efficient handling of string manipulation and counting.

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

• Failing to precompute the necessary arrays efficiently may lead to a brute-force solution with higher time complexity.