01_maxScore.py

'''Time Complexity  O(N)
Given a string s of zeros and ones, return the maximum score after splitting the string into two non-empty substrings (i.e. left substring and right substring).
The score after splitting a string is the number of zeros in the left substring plus the number of ones in the right substring.
Input: s = "011101"
Output: 5 
Explanation: 
All possible ways of splitting s into two non-empty substrings are:
left = "0" and right = "11101", score = 1 + 4 = 5 
left = "01" and right = "1101", score = 1 + 3 = 4 
left = "011" and right = "101", score = 1 + 2 = 3 
left = "0111" and right = "01", score = 1 + 1 = 2 
left = "01110" and right = "1", score = 2 + 1 = 3  '''
class Solution:
  def maxScore(self, s: str) -> int:
    preFix=[]
    count=0
    for i in range(0,len(s)-1):
      if s[i]=='0':
        count+=1
      preFix.append(count)
    preFix.append(0)
    count=0
    for i in range(len(s)-1,0,-1):
      if s[i]=='1':
        count+=1
      preFix[i]=preFix[i]+count
    preFix[0]=preFix[0]+count
    return max(preFix)