Asmiria's Microchip Error Detection

Bit ManipulationMathString

In the veterinary industry, microchips installed in pets are critical for tracking and identification. These microchips contain unique identifiers represented as a large binary number. You are given the binary representation of the microchip ID for Asmiria, a recently rescued cat. This binary string may sometimes include errors due to data corruption during the reading process.\n\nYour task is to write a Java function int correctIdentifier(String binary), which identifies the minimum number of bits that must be flipped to convert the given number into a palindrome. A binary palindrome appears the same when read forwards and backwards.\n\nReturn the minimum number of flips required to transform the binary string into a palindrome.

Example 1

Input

[
  "1001"
]

Output

Explanation. The binary string '1001' is already a palindrome, so no bits need to be flipped.

Example 2

Input

[
  "1101"
]

Output

Explanation. Flipping the last bit from '1' to '0' changes the string to '1100', which is not a palindrome. However, flipping the second bit from '1' to '0' results in the palindrome '1001'.

Example 3

Input

[
  "1111000"
]

Output

Explanation. Flipping the third and sixth bits (both from '1' to '0') transforms '1111000' into '1010001', which is a palindrome.

Example 4

Input

[
  "0"
]

Output

Explanation. A single-bit binary string is trivially a palindrome. No flips are necessary.

Follow-up: What optimizations can be made for extremely long binary strings to reduce the time complexity? Discuss any potential improvements over a simple two-pointer solution.

Constraints:

1. The input string will only consist of characters '0' and '1'.\n2. The length of the input string will be between 1 and 1,000,000 characters.

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