How to deal with bit manipulation with longest binary gap? [duplicate]

Question

I read a little bit and found python-longest-binary-gap SO question

def solution(N):
    max_gap = 0
    new_gap = 0
    for i in range(N.bit_length()):
        if N & (1 << i):
            if new_gap > max_gap:
                max_gap = new_gap
            new_gap =0
        else:
            new_gap += 1
    if new_gap > max_gap:
        max_gap = new_gap
    return max_gap 

The problem is that it gives the wrong solution for 32 (5 instead of 0) or 64. How to fix this?

Answer 1

Here's a pandas solution to this problem:

import pandas as pd

def getlargestgap(x):
  df = pd.DataFrame(list(map(list, bin(x)[2:])), columns=['A'])
  df['B'] = df.groupby(df.A.ne(df.A.shift()).cumsum()).cumcount()+1 
  df['Truth'] = df['A'] == '0'
  return df.loc[df['Truth'] == True]['B'].max() 

getlargestgap(23432124)

# 4