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Updated Feb 23, 2026Created Feb 23, 2026

Monday, 23 February 2026 — Daily 7AM Probability + Statistics Brief

#"probability"#"statistics"#"interview-prep"#"algorithms"

Updated Feb 20, 2026Created Feb 20, 2026

Expected Tosses Until Two Heads in a Row

A clean derivation for E[T] where T is the number of fair coin tosses needed to see HH, using Markov states and a short generating-function/fancy expectation route.

#"probability"#"interview"#"markov-chains"#"expectation"

Updated Feb 16, 2026Created Feb 16, 2026

Python: Longest consecutive-day activity streak per user

Compute each user’s longest consecutive-day streak from event logs in O(n log n) per user (or near O(n) with set-walk variant).

#"python"#"algorithms"#"datetime"#"hashmap"

Updated Feb 13, 2026Created Feb 13, 2026

Rust: First pair that sums to target (O(n))

A quick pattern for finding the first pair whose sum hits a target in one pass.

#"rust"#"algorithms"#"hashmap"