C#: Reverse the strings contained in each pair of matching parentheses in a given string

Last update on June 24 2025 12:58:25 (UTC/GMT +8 hours)

Reverse Strings in Parentheses

Write a C# program to reverse the strings contained in each pair of matching parentheses in a given string. It should also remove the parentheses from the given string.

Sample Solution:

C# Sharp Code:

using System;
using System.Linq;

public class Example
{
    // Function to reverse and remove parentheses from a string
    public static string reverse_remove_parentheses(string str)
    {
        // Find the last index of opening parenthesis '('
        int lid = str.LastIndexOf('(');

        // If no '(' is found, return the original string
        if (lid == -1)
        {
            return str;
        }
        else
        {
            // Find the corresponding closing parenthesis ')' for the found '('
            int rid = str.IndexOf(')', lid);

            // Recursively process the substring inside the parentheses and reverse it
            return reverse_remove_parentheses(
                str.Substring(0, lid) +
                new string(str.Substring(lid + 1, rid - lid - 1).Reverse().ToArray()) +
                str.Substring(rid + 1)
            );
        }
    }

    // Main method to test the reverse_remove_parentheses function
    public static void Main()
    {
        // Test the reverse_remove_parentheses function with different strings and print the results
        Console.WriteLine(reverse_remove_parentheses("p(rq)st"));       // Output: prqst
        Console.WriteLine(reverse_remove_parentheses("(p(rq)st)"));     // Output: pqrst
        Console.WriteLine(reverse_remove_parentheses("ab(cd(ef)gh)ij")); // Output: abcefdghij
    }        
}

Sample Output:

pqrst
tsrqp
abhgefdcij

Flowchart:

For more Practice: Solve these Related Problems:

Write a C# program to reverse the content inside nested parentheses and remove all parentheses.
Write a C# program to reverse text between curly braces instead of parentheses.
Write a C# program to reverse all vowel-containing substrings enclosed in parentheses.
Write a C# program to reverse strings between the first and last occurrence of matching parentheses.

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