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Mobile App Performance Optimization

MediumCoding00:00
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Welcome to your interview.

The question is on your right: Mobile App Performance Optimization. Take a moment with it first.

Talk your thinking through with me if you like - when you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes). Discussion and graded submissions share your five interviewer interactions, so spend them well.

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Problem

Explain how you would optimize a mobile app that feels slow in common user flows. Describe how you would identify bottlenecks, what code patterns you would inspect first, and how you would decide which fixes to ship first.

What to Cover

  • How you profile and reproduce the issue
  • How arrays, strings, and hash-table usage affect performance
  • How you reduce repeated work in hot paths
  • How you prioritize fixes by user impact

Performance Signals

  • Slow startup
  • Dropped frames while scrolling
  • Laggy screen transitions
  • High memory usage
  • Repeated expensive computations