Remove consecutive alphabets which are in same case

Given a string str, the task is to remove consecutive characters from the string that are in same case (Uppercase or Lowercase) and print the resultant string.

Examples:

Input: str = “GeeksForGeeks” 
Output: GeFoGe

Input: str = “abcDEFghi” 
Output: aDg 

Approach:

• Print the first character as it is.
• Traverse through all the other characters in the string starting from second character.
• Compare the current and the previous characters: 
  • If the current and the previous characters are in the same case then skip.
  • Else print the current character.

Below is the implementation of the above approach: 

C++

// C++ program to remove the consecutive characters
// from a string that are in same case
#include <bits/stdc++.h>
using namespace std;

// Function to return the modified string
string removeChars(string s)
{
    string modifiedStr = "";
    modifiedStr += s[0];

    // Traverse through the remaining
    // characters in the string
    for (int i = 1; i < s.length(); i++) {

        // If the current and the previous
        // characters are not in the same
        // case then take the character
        if (isupper(s[i]) && islower(s[i - 1])
            || islower(s[i]) && isupper(s[i - 1]))
            modifiedStr += s[i];
    }

    return modifiedStr;
}

// Driver code
int main()
{
    string s = "GeeksForGeeks";
    cout << removeChars(s);
    return 0;
}

Java

// Java program to remove the consecutive characters
// from a string that are in same case

class GFG
{

    // Function to return the modified string
    static String removeChars(String s)
    {
        String modifiedStr = "";
        modifiedStr += s.charAt(0);

        // Traverse through the remaining
        // characters in the string
        for (int i = 1; i < s.length(); i++)
        {

            // If the current and the previous
            // characters are not in the same
            // case then take the character
            if (Character.isUpperCase(s.charAt(i)) && Character.isLowerCase(s.charAt(i - 1)) ||
                Character.isLowerCase(s.charAt(i)) && Character.isUpperCase(s.charAt(i - 1)))
                modifiedStr += s.charAt(i);
        }

        return modifiedStr;
    }

    // Driver code
    public static void main(String []args)
    {
        String s = "GeeksForGeeks";
        System.out.println(removeChars(s));
    }
}

// This code is contributed
// by ihritik

Python3

# Python3 program to remove the consecutive
# characters from a string that are in same case

# Function to return the modified string
def removeChars(s) :

    modifiedStr = ""
    modifiedStr += s[0]

    # Traverse through the remaining
    # characters in the string
    for i in range(1, len(s)) :

        # If the current and the previous
        # characters are not in the same
        # case then take the character
        if (s[i].isupper() and s[i - 1].islower() or
            s[i].islower() and s[i - 1].isupper()) :

            modifiedStr += s[i]

    return modifiedStr

# Driver code
if __name__ == "__main__" :

    s = "GeeksForGeeks"
    print(removeChars(s))

# This code is contributed by Ryuga

C#

// C# program to remove the consecutive characters
// from a string that are in same case
using System;

class GFG
{

// Function to return the modified string
static string removeChars(string s)
{
    string modifiedStr = "";
    modifiedStr += s[0];

    // Traverse through the remaining
    // characters in the string
    for (int i = 1; i < s.Length; i++)
    {

        // If the current and the previous
        // characters are not in the same
        // case then take the character
        if (char.IsUpper(s[i]) && char.IsLower(s[i - 1]) ||
            char.IsLower(s[i]) && char.IsUpper(s[i - 1]))
            modifiedStr += s[i];
    }

    return modifiedStr;
}

// Driver code
public static void Main()
{
    string s = "GeeksForGeeks";
    Console.Write(removeChars(s));
}
}

// This code is contributed
// by Akanksha Rai

PHP

<?php
// PHP program to remove the consecutive characters
// from a string that are in same case

// Function to return the modified string
function removeChars($s)
{
    $modifiedStr = "";
    $modifiedStr = $modifiedStr . $s[0];

    // Traverse through the remaining
    // characters in the string
    for ($i = 1; $i < strlen($s); $i++)
    {

        // If the current and the previous
        // characters are not in the same
        // case then take the character
        if (ctype_upper($s[$i]) && ctype_lower($s[$i - 1]) ||
            ctype_lower($s[$i]) && ctype_upper($s[$i - 1]))
            $modifiedStr = $modifiedStr . $s[$i];
    }

    return $modifiedStr;
}

// Driver code
$s = "GeeksForGeeks";
echo removeChars($s);

// This code is contributed by ita_c
?>

Javascript

<script>

// JavaScript program to remove
// the consecutive characters
// from a string that are in same case

    // Function to return the modified string
    function removeChars(s)
    {
        let modifiedStr = "";
        modifiedStr += s[0];

        // Traverse through the remaining
        // characters in the string
        for (let i = 1; i < s.length; i++)
        {

            // If the current and the previous
            // characters are not in the same
            // case then take the character
            if (s[i] == (s[i]).toUpperCase() &&
            (s[i - 1])==(s[i - 1]).toLowerCase() ||
                s[i]==s[i].toLowerCase() &&
                (s[i - 1])==(s[i - 1]).toUpperCase())
                modifiedStr += s[i];
        }

        return modifiedStr;
    }

    // Driver code
    let s = "GeeksForGeeks";
    document.write(removeChars(s));



// This code is contributed by avanitrachhadiya2155

</script>

Output

GeFoGe

Complexity Analysis:

• Time Complexity: O(n)
• Auxiliary Space: O(1)