Syntax error Program to find how max score we can get by removing 10 or 01 from binary string in Python

Program to find how max score we can get by removing 10 or 01 from binary string in Python

Suppose we have a binary string s and two values zero_one and one_zero. Now let us consider an operation where we can delete any substring "01" and receive zero_one points. Or we can remove any substring "10" and receive one_zero points. We have to find the maximum number of points we can get after any number of operations.

So, if the input is like s = "10100101" zero_one = 3 one_zero = 2, then the output will be 11, as we can remove "01" three times to get 3*3 = 9 points. Then the remaining string is 10. By removing this we can get another 2 points so the total is 11.

To solve this, we will follow these steps −

  • A := a list of bits given as input string

  • if zero_one < one_zero, then

    • swap zero_one and one_zero

    • for i in range 0 to size of A, do

      • A[i] := A[i] XOR 1

  • ans := 0

  • stack := a new stack

  • for each x in A, do

    • if stack is not empty and stack top element < x, then

      • pop from stack

      • ans := ans + zero_one

    • otherwise,

      • push x into stack

  • ans := ans + one_zero * minimum of occurrence of 0 in stack and occurrence of 1 in stack

  • return ans

Example (Python)

Let us see the following implementation to get a better understanding −

 Live Demo

class Solution:
   def solve(self, S, zero_one, one_zero):
      A = list(map(int, S))
      if zero_one < one_zero:
         zero_one, one_zero = one_zero, zero_one
         for i in range(len(A)):
            A[i] ^= 1
         ans = 0
         stack = []
         for x in A:
            if stack and stack[-1] < x:
               stack.pop()
               ans += zero_one
            else:
               stack.append(x)
         ans += one_zero * min(stack.count(0), stack.count(1))
         return ans
ob = Solution()
s = "10100101"
zero_one = 3
one_zero = 2
print(ob.solve(s, zero_one, one_zero))

Input

"10100101", 3, 2

Output

11
Updated on: 2020-12-22T10:13:26+05:30

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