The Complement Hunt

A easy Python interview practice problem on DataDriven. Write and execute real python code with instant feedback.

Domain

Python

Difficulty

easy

Seniority

L4

Problem

A fraud monitor ingests a stream of transaction `amounts` in arrival order, watching for two that were split to reach a flagged `target`. As each amount arrives, report the position of the earliest earlier amount that pairs with it to reach the target, or `-1` if no earlier amount does.

Summary

Every number is looking for its other half.

Practice This Problem

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