Minimum Number of Changes to Make Binary String Beautiful

class Solution {
public:
    int minimumEditSteps(string str) {
        int editsNeeded = 0;

        for (int idx = 0; idx < str.length() - 1; idx += 2) {
            if (str[idx] != str[idx + 1]) {
                editsNeeded++;
            }
        }

        return editsNeeded;
    }
};

This C++ solution finds the minimum number of changes needed to make a binary string beautiful. A binary string is considered beautiful if every pair of consecutive characters contains distinct characters. The solution involves iterating through the binary string in steps of 2 using a loop. For each character pair, if the current and the next character are the same, an increment to the counter editsNeeded is done to indicate a necessary edit. The function returns the total count of such required changes to achieve a beautiful string.

• The function minimumEditSteps takes a string str as its argument.
• A variable editsNeeded initializes to zero to count the necessary edits.
• A for-loop runs through the string checking every two consecutive characters.
• If the characters are identical, the counter editsNeeded is incremented.
• Ultimately, the function returns the value of editsNeeded that represents the minimum number of edits required.

class Solution {

    public int minimumEdits(String str) {
        int editsNeeded = 0;

        for (int idx = 0; idx < str.length(); idx += 2) {
            if (str.charAt(idx) != str.charAt(idx + 1)) {
                editsNeeded++;
            }
        }

        return editsNeeded;
    }
}

The problem requires calculating the minimum number of changes to make a binary string beautiful; a binary string is termed "beautiful" if no two consecutive characters in the string are the same. The Java solution provided involves a method named minimumEdits, which processes the string to determine how many edits are necessary.

The code operates as follows:

1. Initialize an editsNeeded counter to track the number of changes.
2. Loop through the characters in the binary string. The loop increments by two, checking pairs of adjacent characters.
3. For each character pair, if the two characters are the same, increment the editsNeeded counter by one.
4. Return the value of editsNeeded.

This method effectively counts the number of adjacent similar characters in pairs, incrementing the counter each time a pair of identical characters is found. This count gives the minimum edits needed to ensure no two consecutive characters are the same, ensuring the binary string becomes "beautiful."

The logic executes in O(n/2) time complexity where n is the length of the string, since it examines the string in steps of two. This makes the method efficient, especially for large strings, by minimizing the number of iterations needed.

class Solution:
    def minimumAdjustments(self, s: str) -> int:
        required_changes = 0
        for idx in range(0, len(s), 2):
            if s[idx] != s[idx + 1]:
                required_changes += 1
        return required_changes

The Python solution provided addresses the problem of converting a binary string into a beautiful string where each pair of adjacent characters are the same. The solution uses a straightforward approach to count the minimum number of swaps required:

• Initialize a counter required_changes to zero.
• Iterate over the characters in the string in steps of 2.
• For each pair, compare the characters. If they are not the same, increase the required_changes counter by one.
• Return the required_changes value, which indicates the minimum adjustments needed.

This method ensures that the string is examined efficiently, by only checking pairs rather than every single character, leading to an optimal solution for the given problem.