Data Structures and Algorithms · Techniques

Two pointers

Walking two indices through a sequence at once to avoid a nested loop.

Also known as: fast and slow pointers, left-right pointers.

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• Arrays: A fixed-layout, contiguous block of memory where any index is reached in constant time.

Leads to

• Sliding window: Growing and shrinking a contiguous range over a sequence to track a running condition in one pass.

Related topics

• Sliding window: Growing and shrinking a contiguous range over a sequence to track a running condition in one pass.
• Binary search: Repeatedly halving a sorted range to find a target in logarithmic time.