Number of Changing Keys solution and explanation

def count_key_changes(s: str) -> int:
    count = 0
    for i in range(1, len(s)):
        if s[i].lower() != s[i-1].lower():
            count += 1
    return count

s = "aAbBcC"
print(count_key_changes(s))

public class KeyChangeCounter {
    public static int countKeyChanges(String s) {
        int count = 0;
        for (int i = 1; i < s.length(); i++) {
            if (Character.toLowerCase(s.charAt(i)) != Character.toLowerCase(s.charAt(i - 1))) {
                count++;
            }
        }
        return count;
    }

    public static void main(String[] args) {
        String s = "aAbBcC";
        System.out.println(countKeyChanges(s));
    }
}

#include <iostream>
#include <cctype>

int countKeyChanges(const std::string& s) {
    int count = 0;
    for (size_t i = 1; i < s.length(); ++i) {
        if (tolower(s[i]) != tolower(s[i-1])) {
            count++;
        }
    }
    return count;
}

int main() {
    std::string s = "aAbBcC";
    std::cout << countKeyChanges(s) << std::endl;
    return 0;
}

function countKeyChanges(s) {
    let count = 0;
    for (let i = 1; i < s.length; i++) {
        if (s[i].toLowerCase() !== s[i - 1].toLowerCase()) {
            count++;
        }
    }
    return count;
}

const s = "aAbBcC";
console.log(countKeyChanges(s));

#include <stdio.h>
#include <ctype.h>

int countKeyChanges(const char* s) {
    int count = 0;
    for (int i = 1; s[i] != '\0'; i++) {
        if (tolower(s[i]) != tolower(s[i-1])) {
            count++;
        }
    }
    return count;
}

int main() {
    const char* s = "aAbBcC";
    printf("%d\n", countKeyChanges(s));
    return 0;
}

using System;

class Program {
    static int CountKeyChanges(string s) {
        int count = 0;
        for (int i = 1; i < s.Length; i++) {
            if (char.ToLower(s[i]) != char.ToLower(s[i - 1])) {
                count++;
            }
        }
        return count;
    }

    static void Main() {
        string s = "aAbBcC";
        Console.WriteLine(CountKeyChanges(s));
    }
}

function countKeyChanges(s) {
    const segments = s.match(/(.)\1*/gi) || [];
    return segments.length - 1;
}

const s = "aAbBcC";
console.log(countKeyChanges(s));

using System;
using System.Text.RegularExpressions;

class Program {
    static int CountKeyChanges(string s) {
        // Regular Expression to split string into blocks of same ignore-case keys
        var regex = new Regex("((?<=[a-zA-Z\0])(?<!\G(?i)(?<=.))(?![^\1]{2}))", RegexOptions.IgnoreCase);
        var matchCollection = regex.Split(s);
        return matchCollection.Length - 1;
    }

    static void Main() {
        string s = "aAbBcC";
        Console.WriteLine(CountKeyChanges(s));
    }
}

function countKeyChanges(s: string): number {
    s = s.toLowerCase();
    let ans = 0;
    for (let i = 1; i < s.length; ++i) {
        if (s[i] !== s[i - 1]) {
            ++ans;
        }
    }
    return ans;
}

func countKeyChanges(s string) (ans int) {
	s = strings.ToLower(s)
	for i, c := range s[1:] {
		if byte(c) != s[i] {
			ans++
		}
	}
	return
}

impl Solution {
    pub fn count_key_changes(s: String) -> i32 {
        let s = s.to_lowercase();
        let bytes = s.as_bytes();
        let mut ans = 0;
        for i in 1..bytes.len() {
            if bytes[i] != bytes[i - 1] {
                ans += 1;
            }
        }
        ans
    }
}