Competitive ProgrammingEasy

Count Binary Strings

Detailed guide and Python implementation for the 'Count Binary Strings' problem.

Problem Statement

Easy

Write a function count_binary_strings(n) that returns the number of binary strings of length n that do not contain any consecutive 1s.

Constraints
  • 1 <= n <= 45

Examples

Example 1
Input
count_binary_strings(2)
Output
3
Explanation

The valid strings of length 2 are '00', '01', and '10'.

Example 2
Input
count_binary_strings(3)
Output
5
Explanation

The valid strings of length 3 are '000', '001', '010', '100', and '101'.

Need a Hint?
Consider using Dynamic Programming-specific data structures like sets or heaps.
Edge Cases to Watch
  • Empty input structures
  • Single element inputs
  • Large numerical bounds

Ready to Solve?

Open the problem in PyRun's browser-based Python editor. Your code runs fully offline — no server required.

Open in Editor

Recommended Python Resources

Expand your knowledge with related interactive tutorials, cheat sheets, and code comparisons.