2914. Minimum Number of Changes to Make Binary String Beautiful

You are given a 0-indexed binary string s having an even length.

A string is beautiful if it’s possible to partition it into one or more substrings such that:

• Each substring has an even length.
• Each substring contains only 1‘s or only 0‘s.

You can change any character in s to 0 or 1.

Return the minimum number of changes required to make the string s beautiful.

class Solution {
public:
    int minChanges(string s) {
        int res = 0;
        for(int i = 0; i < s.length(); i += 2) {
            if(s[i] != s[i+1]) res += 1;
        }
        return res;
    }
};