divide·conquer·结合·位运算·操作 模式
2 道题目
模式页适合用来建立可复用解题框架。先识别题目特征，再按固定流程解释状态定义、转移和边界。
识别信号
- Expect candidates to recognize bit-level patterns and swap sequences.
- Look for proper handling of masks and shifts without off-by-one errors.
- The interviewer wants bit-level reasoning, not string conversion or decimal digit counting.
解题流程
- 1. 明确窗口/状态定义
- 2. 更新状态并维护约束
- 3. 用边界样例验证
常见失分点
- Incorrectly swapping bits without using proper masks leading to wrong output.
- Counting decimal 1s in the number instead of set bits in the binary representation.