Sliding Window — Reasoning Check

1. For positive values [2,1,5,2,3,2] and target 8, what is the minimum qualifying subarray length? Enter one integer.

2. Apply the positive-sum shrinking template to [1,-1,5] with target 5. It records length 3, removes the first 1, then stops because the sum is 4. What went wrong?

Select one answer.

The answer should be updated only after every removal, which fixes arbitrary negative values. A target equal to an input value requires a separate equality branch in every sliding-window algorithm. Removing the next negative value would increase the sum, so stopping after invalidity can miss a shorter valid window.

3. What is the longest substring length without repeated bytes in "dvdf"? Enter one integer.

4. Minimum Window Substring tracks formed character kinds for target "AAB". The active window contains AAA B. What happens when one A leaves?

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Formed decreases because any required character leaving breaks coverage. Formed increases because the remaining window has fewer surplus characters. The A count drops from 3 to 2, so formed stays unchanged.

5. For text "zcatdogcat" and words ["cat","dog"], how many concatenation start positions match? Enter one integer.

6. Character Replacement keeps a historical maxFreq while left moves forward. Which change would make the expression windowLength-maxFreq certify the CURRENT window as valid?

Select one answer.

Recompute maxFreq from the active counts after removals. Reset maxFreq to zero whenever left moves, without examining the remaining counts. Keep the historical maxFreq and assume every retained window needs at most k replacements.