从字符串中删除给定字符的第一次和最后一次出现

给定一个字符C和一个字符串S ，任务是从字符串S中删除字符C的第一次出现和最后一次出现。
例子：

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

方法：
想法是从两端遍历给定的字符串，找到遇到的字符C的第一个匹配项，并删除相应的匹配项。最后，打印结果字符串。
下面是上述方法的实现：

C++

// C++ Program to implement
// the above approach
#include 
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

输出：

helo word

时间复杂度： O(N)
辅助空间： O(1)

方法2：使用索引方法

• 将字符串转换为列表。
• 遍历列表，如果找到给定字符，则使用pop()删除该索引并中断循环
• 从末尾遍历列表，如果找到给定字符，则使用pop()删除该索引并中断循环。
• 加入列表并打印。

下面是实现：

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

时间复杂度： O(N)

辅助空间： O(N)