Status: Solved
Priority: Medium
Security: Public
Views: 168
Last Modified: 2016-09-22

nestparen challenge

Hi,

I am working on below challenge

http://codingbat.com/prob/p183174

Recursion-1 > nestParen
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Given a string, return true if it is a nesting of zero or more pairs of parenthesis, like "(())" or "((()))". Suggestion: check the first and last chars, and then recur on what's inside them.

nestParen("(())") → true
nestParen("((()))") → true
nestParen("(((x))") → false

i was not clear on description. please advies

gudii9

Asked: 2016-09-21

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1 Solution

LVL 37

zzynxSoftware engineerCommented: 2016-09-22

You have to check if each opening bracket '(' in the string has a corresponding closing bracket ')'

LVL 7

gudii9Author Commented: 2016-09-22

i understood now. let me think

LVL 7

gudii9Author Commented: 2016-09-22

public boolean nestParen(String str) {

if(str.equals("")){
  return true;
}
else if( str.charAt(0)=='(' && str.charAt(str.length()-1) ==')'  ){
  
  return nestParen(str.substring(1,str.length()-1));
}
else{
  return false;
}
}

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above passes ll tests. any improvements or alternate approaches?

LVL 37

zzynxSoftware engineerCommented: 2016-09-22

Not really.

public boolean nestParen(String str) {
   if(str.length()==0){
     return true;
   }
   if( str.charAt(0)=='(' && str.charAt(str.length()-1) ==')' ){
     return nestParen(str.substring(1,str.length()-1));
   }
   return false;
}

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