Solving Number of Substrings Containing All using Sliding Window.

Problem

Solve Number of Substrings Containing All.

Pattern

This problem demonstrates the Sliding Window pattern.

Approach

Expand and shrink window.

Solution 

  // solution

Complexity

O(n)

Best Practices

  • Identify the pattern before coding — pattern recognition saves time
  • Handle edge cases: empty input, single element, duplicates
  • Use descriptive variable names even in timed interviews
  • Test with the provided examples plus one custom case