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schemaReusable solving pattern

string plus counting Pattern

Pattern hubs are for building transferable solving frames. Learn the recognition signals first, then drill state definition, update rules, and edge explanation until the pattern feels stable.

database3 problemstune2/1/0 difficulty mixcategory2 linked topics

Pattern brief

Recognize first

Check for simultaneous overlapping croaks to assess string plus counting comprehension.

Solve rhythm

State the active state and invariant first, explain how each update preserves them, then pressure-test with counterexamples.

Most common miss

Failing to track multiple frogs simultaneously, leading to undercounting.

Recognition signals

  • Check for simultaneous overlapping croaks to assess string plus counting comprehension.
  • Look for proper validation of sequence order to detect partial or invalid croaks.
  • The candidate correctly splits the string into two halves without index errors.

Solve flow

  1. 1. Define the active state/window.
  2. 2. Update state while preserving invariants.
  3. 3. Validate with edge-heavy examples.

Common misses

  • Failing to track multiple frogs simultaneously, leading to undercounting.
  • Forgetting to include uppercase vowels in the count.
  • Replacing underscores inconsistently reduces maximum distance.

Recommended Ladder

Problem bank

string plus counting pattern bank

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String plus Counting LeetCode Pattern: 3 Solutions