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

PythonServer Side ProgrammingProgramming

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