Sum at Level i Binary Tree

Sum at Level i Binary Tree

  September 08, 2017    

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Problem :

Given a binary tree and a number i, the task is to find sum of tree nodes at level i. The Binary Tree given in string form: (node-value(left-subtree)(right-subtree))


Idea is to count opening brackets , if no. of opening bracket is == level+1 then it means now we are at level k , add this number to sum.

Code:

import java.util.*;
import java.lang.*;
import java.io.*;
class hackerranksolutionc
 {
public static void main (String[] args)
{
Scanner ab=new Scanner(System.in);
int t=Integer.parseInt(ab.nextLine().trim());
while(t-->0)
{
   int n=Integer.parseInt(ab.nextLine().trim());
   String str=new String(ab.nextLine().trim());
   //System.out.println(str);
   int c=0,sum=0;
   for(int i=0;i<str.length();++i)
   {
       if(str.charAt(i)=='(')
       {
           ++c;
           ++i;
           int val=0;
           while(i<str.length() && (str.charAt(i)!=')' && str.charAt(i)!='('))
           {
               if(c==n+1)
               {
                   val=val*10+str.charAt(i)-'0';
               }
               ++i;
           }
           if(val!=0)
           sum+=val;
           //System.out.println(val+" ( fnd "+i+" ");
           }
           
           if(i<str.length() && str.charAt(i)==')')
           --c;
           else if(i<str.length() && str.charAt(i)=='(')
           --i;
   }
   System.out.println(sum);
}
}
}