Add sliding-window module: 12 sliding window and two-pointer interview problems, brute-force cross-checks, dry-run traces, operation counts, pitfalls (11 tests)

Co-Authored-By: Claude Sonnet 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_017ic4b6EqSkUWKNBc8i3Q3U
2026-11-09 08:40:07 +00:00
parent 4a9021d936
commit 911aef5515
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+Operation counts, brute force vs window / two pointers (counted, not timed)
+===========================================================================
+
+Max sum of k=100 consecutive elements: element reads
+       n    brute force sliding window    ratio
+    1000         90,100          1,900    47.4x
+    2000        190,100          3,900    48.7x
+    4000        390,100          7,900    49.4x
+    8000        790,100         15,900    49.7x
+
+Pair search, target absent (worst case) in a sorted array 0..n-1: checks / steps
+       n      all pairs   two pointers
+    1000        499,500            999
+    2000      1,999,000          1,999
+    4000      7,998,000          3,999
+    8000     31,996,000          7,999
+
+minWindow on random strings over A-D, t="ABCD" (seed 42): pointer moves
+The loop is nested but each pointer only moves forward, so total moves stay linear.
+       n  right moves  left moves  valid windows
+    1000        1,000         996            996
+    2000        2,000       1,996          1,996
+    4000        4,000       3,996          3,996
+    8000        8,000       7,993          7,993