CareerCup

String findParenthesis(String s) {
	if(s.charAt(0) == '(') {
		if(s.charAt(s.length()-1) == ')')
			return s;
		else return findParenthesis(s.substring(0, s.length()-1));
	} else {
		return findParenthesis(s.substring(1));
	}
}

function findSinglePairOfParenthesis(string n) {
	if (n == null) return null;
	// Go to the end of the string
	while (*n != '\0') n++;
	if (n == '\0') return null;
	// Find closing bracket
	while (*n != ')') n--;
	// Terminate the string right in place
	n++;
	*n = '\0';
	// Find opening bracket
	while (*n != '(') n--;
	
	return n;
}

Good Answer provided by Sunny. Very near solution in C#

IEnumerable<string> GetValue(string val)
        {
            while (val.Length != 0)
            {
                if(val.Substring(0,1) == "(")
                {
                    while(val.Substring(0,1) != ")")
                    {
                        yield return val.Substring(0, 1);
                        val = val.Substring(1);
                    }
                    yield return val.Substring(0, 1);
                }
                val = val.Substring(1);
            }
            yield return string.Empty;
        }

Here's python version without explicit variables

def find_start(input_string):
	if input_string.startswith("("):
		return input_string
	return find_start(input_string[1:])

def find_end(input_string):
	if input_string.endswith(")"):
		return input_string
	return find_end(input_string[:-1])


def in_parenthesis(input_string):
	return find_end(find_start(input_string))

Pseudo Code

for(Each char in String S){
Compute the ASCII value of the char;
If the ASCII Value matches the one corresponding to '('
Return (The values from the current char to the position where it again matches the ASCII value for ')' )
}

Run Time - O(n)

def printInsideParens(s):
    if s[0] == '(':
        print '(',
        printUntilOutside(s[1:])
    else:
        printInsideParens(s[1:])


def printUntilOutside(s):
    if s[0] != ')':
        print s[0],
        printUntilOutside(s[1:])
    else:
        print ')'

//IN JAVA 
//finding the string within the given parenthesis without using variables
public class Parenthesis {
	public static void main(String[] args) {
		System.out.println(parenthesis("k(us)hal"));
	}

	public static String parenthesis(String input) {

		if (!Character.toString(input.charAt(0)).equals("(")) {

			return parenthesis(input.substring(1));
		} else if (!Character.toString(input.charAt(input.length() - 1))
				.equals(")")) {

			return parenthesis(input.substring(0, input.length() - 1));
		} else {
			return input;
		}

	}
}

#include<stdio.h>
#include<string.h>
int main()
{
char *s="xyz(abc)123";
while(s[0]!='(')
s++;
while(s[0]!=')')
{
printf("%c",s[0]);
s++;
}
printf(")");
}

python execution:

a = 'xyz(abc)123'
a.split('(')[1].split(')')[0]