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Remove the first and last occurrence of a given Character from a String

  • Difficulty Level : Easy
  • Last Updated : 31 May, 2021

Given a character C and a string S, the task is to remove the first and last occurrence of the character C from the string S.

Examples:

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Input: S = “GeekforGeeks”, C = ‘e’ 
Output: GeksforGeks 
Explanation: 
GeekforGeeks -> GekforGeks



Input: S = “helloWorld”, C = ‘l’ 
Output: heloWord

Approach: 
The idea is to traverse the given string from both ends and find the first occurrence of the character C encountered and remove the corresponding occurrences. Finally, print the resultant string.
Below is the implementation of the above approach:

C++




// C++ Program to implement
// the above approach
#include <bits/stdc++.h>
using namespace std;
 
// Function to remove first and last
// occurrence of a given character
// from the given string
string removeOcc(string& s, char ch)
{
    // Traverse the given string from
    // the beginning
    for (int i = 0; s[i]; i++) {
 
        // If ch is found
        if (s[i] == ch) {
            s.erase(s.begin() + i);
            break;
        }
    }
 
    // Traverse the given string from
    // the end
    for (int i = s.length() - 1;
        i > -1; i--) {
 
        // If ch is found
        if (s[i] == ch) {
            s.erase(s.begin() + i);
            break;
        }
    }
 
    return s;
}
 
// Driver Code
int main()
{
    string s = "hello world";
 
    char ch = 'l';
 
    cout << removeOcc(s, ch);
    return 0;
}

Java




// Java Program to implement
// the above approach
class GFG{
 
// Function to remove first and last
// occurrence of a given character
// from the given String
static String removeOcc(String s, char ch)
{
    // Traverse the given String from
    // the beginning
    for (int i = 0; i < s.length(); i++)
    {
 
        // If ch is found
        if (s.charAt(i) == ch)
        {
            s = s.substring(0, i) +
                s.substring(i + 1);
            break;
        }
    }
 
    // Traverse the given String from
    // the end
    for (int i = s.length() - 1; i > -1; i--)
    {
 
        // If ch is found
        if (s.charAt(i) == ch)
        {
            s = s.substring(0, i) +
                s.substring(i + 1);
            break;
        }
    }
    return s;
}
 
// Driver Code
public static void main(String[] args)
{
    String s = "hello world";
 
    char ch = 'l';
 
    System.out.print(removeOcc(s, ch));
}
}
 
// This code is contributed by sapnasingh4991

Python3




# Python3 program to implement
# the above approach
 
# Function to remove first and last
# occurrence of a given character
# from the given string
def removeOcc(s, ch):
     
    # Traverse the given string from
    # the beginning
    for i in range(len(s)):
 
        # If ch is found
        if (s[i] == ch):
            s = s[0 : i] + s[i + 1:]
            break
     
    # Traverse the given string from
    # the end
    for i in range(len(s) - 1, -1, -1):
 
        # If ch is found
        if (s[i] == ch):
            s = s[0 : i] + s[i + 1:]
            break
 
    return s
 
# Driver Code
s = "hello world"
 
ch = 'l'
 
print(removeOcc(s, ch))
 
# This code is contributed by sanjoy_62

C#




// C# Program to implement
// the above approach
using System;
class GFG{
 
// Function to remove first and last
// occurrence of a given character
// from the given String
static String removeOcc(String s, char ch)
{
    // Traverse the given String from
    // the beginning
    for (int i = 0; i < s.Length; i++)
    {
 
        // If ch is found
        if (s[i] == ch)
        {
            s = s.Substring(0, i) +
                s.Substring(i + 1);
            break;
        }
    }
 
    // Traverse the given String from
    // the end
    for (int i = s.Length - 1; i > -1; i--)
    {
 
        // If ch is found
        if (s[i] == ch)
        {
            s = s.Substring(0, i) +
                s.Substring(i + 1);
            break;
        }
    }
    return s;
}
 
// Driver Code
public static void Main(String[] args)
{
    String s = "hello world";
 
    char ch = 'l';
 
    Console.Write(removeOcc(s, ch));
}
}
 
// This code is contributed by sapnasingh4991

Javascript




<script>
      // JavaScript Program to implement
      // the above approach
      // Function to remove first and last
      // occurrence of a given character
      // from the given String
      function removeOcc(s, ch) {
        // Traverse the given String from
        // the beginning
        for (var i = 0; i < s.length; i++) {
          // If ch is found
          if (s[i] === ch) {
            s = s.substring(0, i) + s.substring(i + 1);
            break;
          }
        }
 
        // Traverse the given String from
        // the end
        for (var i = s.length - 1; i > -1; i--) {
          // If ch is found
          if (s[i] === ch) {
            s = s.substring(0, i) + s.substring(i + 1);
            break;
          }
        }
        return s;
      }
 
      // Driver Code
      var s = "hello world";
      var ch = "l";
 
      document.write(removeOcc(s, ch));
</script>
Output: 
helo word

Time Complexity: O(N) 
Auxiliary Space: O(1)
 

Method #2: Using Index Method

  • Convert the string into a list.
  • Traverse the list and if we find a given character, then remove that index using pop()  and break the loop
  • Traverse the list from the end and if we find a given character, then remove that index using pop()  and break the loop.
  • Join the list and print it.

Below is the implementation:

Python3




# Python3 program to implement
# the above approach
 
# Function to remove first and last
# occurrence of a given character
# from the given string
 
 
def removeOcc(str, ch):
    # Convert string to list
    s = list(str)
    # Traverse the string from starting position
    for i in range(len(s)):
        # if we find ch then remove it and break the loop
        if(s[i] == ch):
            s.pop(i)
            break
    # Traverse the string from the end
    for i in range(len(s)-1, -1, -1):
        # if we find ch then remove it and break the loop
        if(s[i] == ch):
            s.pop(i)
            break
    # Join the list
    return ''.join(s)
 
 
# Driver Code
s = "hello world"
 
ch = 'l'
 
print(removeOcc(s, ch))
 
# This code is contributed by vikkycirus

Time Complexity: O(N) 

Auxiliary Space: O(N)




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