Why segmentation fault

#1
#2

hi @niketagarwal10
you have forgot one condition

if (s==e) return new node(pre[pp++]);

#3

i didnt understand that…whats “pre” ?
also why do we need to take s==e separately when i have put a condition only on s>e…so s<=e should already take for s==e.

#4

errors
for(int i=0;i<a;i++){
cin>>arr1[a];
}
int b;
cin>>b;
int arr2[b];
for(int i=0;i<b;i++){
cin>>arr2[b];
}
these should be arr[i]

it is array containing preorder traversal in your case it is arr1

because this is leave node no need to call left or right

yes you have to take it seprately
because for ex
s=0 e=0
means you are at node with data 3
now you call for left part
root->left=build(arr1,arr2,s,php-1);
which is root->left=build(arr1,arr2,0,-1);
when you access arr[-1] it will give segmentaion fault that’s why you have to take this condition seprately

modified code

#5

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