Reduce array to zero
Given an array of non-negative integers, each operation chooses two indices and subtracts 1 from each if both are positive. Return the minimum number of operations to reduce the array to all zeros, or -1 if impossible.
Squares of Sorted Array
Implement a function that returns a sorted list of squares for a given non-decreasing integer array.
Showing 1–2 of 2 challenges · easy · Two Pointers & Sliding Window
Two Pointers & Sliding Window — Python coding challenges
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This page lists two pointers & sliding window challenges — real Python problems you solve in the browser IDE with instant test feedback. Each challenge includes a clear brief, starter code, and automated checks.
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Challenges test what you can build under constraints. For guided teaching, use our Python tutorials. For quick checks, try quizzes or copy snippets from code samples.