Given an integer ‘K’ and a tree in string format.how to solve below problem ?

[radha gogia]

Given an integer ‘K’ and a tree in string format. We have to print the sum of all elements at Kth level from root.

0
/ \
5 7
/ \ / \
6 4 1 3
\
9



Tree given in the form: (node value(left subtree)(right subtree))
For tree given above: (0(5(6()())(4()(9()())))(7(1()())(3()())))
Input format: K Tree
Output format: Sum
For example, for given tree:
Input: 2 (0(5(6()())(4()(9()())))(7(1()())(3()())))
Output: 14

I am unable to get the approach of starting with this , how to implement it using stack ?

[weaknessforcats]

This is done using recursion.

Have you ever written a recursive function?

[radha gogia]

#include<stdio.h>
#include<string.h>
int main()
{int sum=0;
char str[40];
char *ptr;
int k;
printf("enter string");
gets(str);
printf("enter depth");
scanf("%d",&k);
ptr=str;
int depth =-1;
while(*ptr!='\0')
{
if(*ptr=='(')
{
depth++;
if(depth==k)
{
sum=sum+*(++ptr)-'0';
}
}
else if (*ptr==')')
{
depth--;
}
}
printf("%d", sum);
return 0;
}
 

Started with a depth of -1. Increment the depth when we find a (. Decrement the depth when we find a ). If I encounter a digit when depth is equal to K, then convert the digits to a number, and add the number to the sum.

But this code isn't working ,please help

[weaknessforcats]

Change the code so you don't enter the string for the tree.

The string must be (0(5(6()())(4()(9()())))(7(1()())(3()()))) exactly.

Let me know what happens.

[radha gogia]

I am unable to get your point , I entered this string only as input .

[weaknessforcats]

The tree in the problem can only be this string:

(0(5(6()())(4()(9()())))(7(1()())(3()())))

exactly.
I have no idea what you entered but if it's not exactly this then your code won't work.

By removing the data entry you remove one reason why the code doesn't work.

After all, your program is just a test of your function to iterate the tree, it's not a full fledged app.

[radha gogia]

I got the point , I forgot to increment the pointer , input was correct , thankss a lot