Sum Signed Values in Java with IntStream
Combine absolute values and matching boolean signs with IntStream. Check cancellation, all-negative input, int bounds, and the equal-length array contract.
java / algorithms↗
java11
Practical notes on Java, Spring, testing, and software engineering, with working examples and source references.
Generate an x-Spaced Sequence in Java: Promote Before Multiplication
Build n values from x through x*n with IntStream. Explain why mapToLong alone does not prevent int overflow, and check positive, negative, and zero steps.
java / algorithms↗
Remove Adjacent Duplicate Pairs in Java with an ArrayDeque Stack
Reduce adjacent equal-character pairs with a stack. Explain the prefix invariant, cascading removal, million-character boundaries, and time and space costs.
java / algorithms↗
Find the Missing Runner in Java with Name Frequencies
Subtract completion counts from participant counts with HashMap. Handle duplicate names without Set subtraction and explain the one-missing-runner contract.
java / algorithms↗
Sort Failure Rates in Java: Denominators, Ties, and Long Products
Count stopped and reached players, sort exact rates with long cross-products, and handle unreachable stages, full completion, and stage-number tie-breaking.
java / algorithms↗
Java Ponketmon: Why the Answer Is min(Distinct Types, N/2)
Count distinct types with HashSet and prove the selection bound is achievable. Distinguish the maximum type count from constructing an actual selection.
java / algorithms↗
Java New ID Recommendation: Normalization Order and Truncation
Implement ID normalization with an Optional chain and a loop. Check dot collapsing, empty input after filtering, truncation cleanup, padding, and locale independence.
java / algorithms↗
Java Array Dot Product: IntStream and Integer Bounds
Multiply matching array elements and sum them with IntStream. Understand signs, int bounds, and why wider multiplication must promote operands before overflow.
java / algorithms↗
Convert English Digit Words in Java with String.replace
Normalize valid mixtures of digits and zero-to-nine words using literal replacement. Distinguish replace from replaceAll and explain integer bounds and scope.
java / algorithms↗
Java LRU Cache: Use Access Order in LinkedHashMap
Simulate an LRU cache with access-ordered LinkedHashMap. Check hit refresh, eviction, case-insensitive keys, zero capacity, and the model’s cost assumptions.
java / algorithms↗
Dev digest · 2026-10-25
CSIRO's sBeacon uses Amazon S3, AWS Lambda, Amazon Athena and Amazon DynamoDB to query genomic data while leaving the genomic files in their original storage. In CSIRO's chromosome 1 benchmark with 2504 individuals, sBeacon onboarded a 1.1 GB compressed VCF dataset in 18 seconds. AWS reports that whole-genome range queries time out at API Gateway, and throttled Lambda calls can lose results on HTTP 429 unless the application handles them.
cloud / ai / java↗