avoid global variables with inner functions

30 Nov, 2025 • 50 words • 1 min • updated 03 Jan, 2026

Instead of polluting the global space:

     python
     
ans = 0

def backtrack(...):
  global ans
  ...

backtrack(...)

return ans

Prefer to define an inner function:

     python
     
def main():
  ans = 0

  def backtrack(...):
    ...

  backtrack(...)

main()

There’s no shame in using the scope of the outer function (main in this case).