Data Scientist @Salesforce.com
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Programming Exercise - II ReplaceAll() method in Java.

Hello All, I got some more time to write another piece of a small algorithm tweaking a little bit. Creating an usecase to use replaceAll method.

Question :  I am taking a string as input and I need to find whether it is palindrome or not. It is a simple question as long as we think string doesn’t have any special characters. Ex : “K a,y”ak” should return true as it is a palindrome without any special characters. With our usual approach it won’t. 

Solution : Thanks to Java libraries we have a method called replaceAll which replaces all symbols in our string with whichever ‘value’ we provide.

Syntax : String s;

              s=s.replaceAll(“Regex”,”value”);

 

Lets code using above syntax. Here I want to remove all spaces in my string s and check for palindrome. 

boolean isPalindrome(String s)

{

s = s.replaceAll(” “,”“); // Taking off spaces. We can write “or”(” “|”.”|”%”) operations in the regex method to replace multiple special symbols in our string.

int n = s.length();

if(n%2 ==0)   // Even length

{

for(int i=0;i<n/2- 1 ; i++) // Looping only half

{

if((s.charAt(i) == s.charAt(n-1-i) )

return true;

else

return false;

}

}

else // Odd length

{

for(int i=0; i< n/2 - 1; i++)

{

if(s.charAt(i) == s.charAt(n-1-i) )

{

return true;

}

else

return false;

}

}

}

Suggestions and inputs are most welcome.