Print the string by ignoring alternate occurrences of any character

Difficulty Level : Easy
Last Updated : 20 May, 2021

Given a string of both uppercase and lowercase alphabets, the task is to print the string with alternate occurrences of any character dropped(including space and consider upper and lowercase as same).
Examples:

Input : It is a long day Dear.
Output : It sa longdy ear.
Print first I and then ignore next i.
Similarly print first space then 
ignore next space.


Input : Geeks for geeks
Output : Geks fore

Asked in: Microsoft

As we have to print characters in an alternate manner, so start traversing the string and perform following two steps:-

Increment the count of occurrence of current character in a hash table.
Check if the count becomes odd, then print the current character, else not.

C++

// C++ program to print the string in given pattern
#include <bits/stdc++.h>
using namespace std;
 
// Function to print the string
void printStringAlternate(string str)
{
    unordered_map<char, int> occ;
 
    // Start traversing the string
    for (int i = 0; i < str.length(); i++) {
 
        // Convert uppercase to lowercase
        char temp = tolower(str[i]);
 
        // Increment occurrence count
        occ[temp]++;
 
        // If count is odd then print the character
        if (occ[temp] & 1)
            cout << str[i];
    }
 
    cout << endl;
}
 
// Drivers code
int main()
{
    string str = "Geeks for geeks";
    string str2 = "It is a long day Dear";
 
    printStringAlternate(str);
    printStringAlternate(str2);
 
    return 0;
}

Java

// Java program to print the string in given pattern
import java.io.*;
 
class GFG
{
    // Function to print the string
    static void printStringAlternate(String str)
    {
        int[] occ = new int[122];
         
        // Convert uppercase to lowercase
        String s = str.toLowerCase();
  
        // Start traversing the string
        for (int i = 0; i < str.length(); i++)
        {
             
            char temp = s.charAt(i);
  
            // Increment occurrence count
            occ[temp]++;
  
            // If count is odd then print the character
            if (occ[temp]%2 != 0)
                System.out.print(str.charAt(i));
        }
        System.out.println();
    }
     
    // driver program
    public static void main (String[] args)
    {
        String str1 = "Geeks for geeks";
        String str2 = "It is a long day Dear";
        printStringAlternate(str1);
        printStringAlternate(str2);
    }
}
 
// Contributed by Pramod Kumar

Python3

# Python3 program to print the string
# in given pattern
 
# Function to print the string
def printStringAlternate(string):
 
    occ = {}
 
    # Start traversing the string
    for i in range(0, len(string)):
 
        # Convert uppercase to lowercase
        temp = string[i].lower()
 
        # Increment occurrence count
        occ[temp] = occ.get(temp, 0) + 1
 
        # If count is odd then print the character
        if occ[temp] & 1:
            print(string[i], end = "")
 
    print()
 
# Driver code
if __name__ == "__main__":
 
    string = "Geeks for geeks"
    string2 = "It is a long day Dear"
 
    printStringAlternate(string)
    printStringAlternate(string2)
 
# This code is contributed by Rituraj Jain

C#

// C# program to print the
// string in given pattern
using System;
         
public class GFG {
     
    // Function to print the string
    static void printStringAlternate(String str)
    {
        int[] occ = new int[122];
         
        // Convert uppercase to lowercase
        string s = str.ToLower();
 
 
        // Start traversing the string
        for (int i = 0; i < str.Length; i++)
        {
             
            char temp = s[i];
 
            // Increment occurrence count
            occ[temp]++;
 
            // If count is odd then print
            // the character
            if (occ[temp] % 2 != 0)
                Console.Write(str[i]);
        }
        Console.WriteLine();
    }
     
    // Driver Code
    public static void Main ()
    {
        string str1 = "Geeks for geeks";
        string str2 = "It is a long day Dear";
        printStringAlternate(str1);
        printStringAlternate(str2);
    }
}
 
// This code is contributed by Sam007.

PHP

<?php
// PHP program to print the string
// in given pattern
 
// Function to print the string
function printStringAlternate($str)
{
    $occ = array();
     
    // Convert uppercase to lowercase
    $s = strtolower($str);
 
    // Start traversing the string
    for ($i = 0; $i < strlen($str); $i++)
    {
         
        $temp = $s[$i];
 
        // Increment occurrence count
        $occ[($temp)]++;
 
        // If count is odd
        // then print the character
        if ($occ[$temp] % 2 != 0)
            echo($str[$i]);
    }
    echo "\n";
}
 
// Driver Code
$str1 = "Geeks for geeks";
$str2 = "It is a long day Dear";
printStringAlternate($str1);
printStringAlternate($str2);
 
// This code is contributed by Code_Mech.
?>

Javascript

<script>
 
    // JavaScript program to print the
    // string in given pattern
     
    // Function to print the string
    function printStringAlternate(str)
    {
        let occ = new Array(122);
        occ.fill(0);
           
        // Convert uppercase to lowercase
        let s = str.toLowerCase();
   
   
        // Start traversing the string
        for (let i = 0; i < str.length; i++)
        {
               
            let temp = s[i];
   
            // Increment occurrence count
            occ[temp.charCodeAt()]++;
   
            // If count is odd then print
            // the character
            if (occ[temp.charCodeAt()] % 2 != 0)
                document.write(str[i]);
        }
        document.write("</br>");
    }
     
    let str1 = "Geeks for geeks";
    let str2 = "It is a long day Dear";
    printStringAlternate(str1);
    printStringAlternate(str2);
     
</script>

Output:

Geks fore
It sa longdy ear

This article is contributed by Sahil Chhabra. If you like GeeksforGeeks and would like to contribute, you can also write an article using write.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
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