Check if Binary String has At Most One Segment of Ones in Python

Suppose we have a binary string s (without leading zeros), We have to check whether s contains at most one contiguous segment of ones or not.

So, if the input is like s = "11100", then the output will be True as there is one segment of ones "111".

To solve this, we will follow these steps −

• count := -1

• if size of s is same as 1, then

  • return True

• for each i in s, do

  • if i is same as "1" and count > -1, then

    • return False

  • otherwise when i is same as "0", then

    • count := count + 1

• return True

Let us see the following implementation to get better understanding −

Example

 Live Demo

def solve(s):
   count = -1
   if len(s)==1:
      return True
   for i in s:
         if i=="1" and count>-1:
            return False
         elif i=="0":
            count+=1
   return True
s = "11100"
print(solve(s))

Input

11100

Output

True