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Print the string by ignoring alternate occurrences of any character

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  • Difficulty Level : Easy
  • Last Updated : 14 Jul, 2022
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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. 

Implementation:

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

Time complexity : O(n) 
Auxiliary Space : O(n)

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 review-team@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks. 


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