Sliding Window (Variable Size)

The Sliding Window (Variable Size) technique is applied when tackling problems characterized by specific invariants in the problem state or constraints:

• Core Strategy: Expand and shrink a window's right/left edges based on a validity condition to find an optimal-length substring/subarray.
• When to use: Look for opportunities where repeated re-computation can be replaced by maintaining monotonic properties, state windows, or relational pointers.
• Interview Signal: Demonstrating this pattern shows mastery of Sliding Window foundations, reducing worst-case algorithmic complexity.