Recover Binary Search Tree

#1

#include <bits/stdc++.h>
using namespace std;

class node

{

public:
int data;
node*left;
node*right;
node(int d)
{
    data=d;
    left=NULL;
    right=NULL;
}

};

int i;

node* builttree()

{

int d;
cin>>d;
if(d==-1)
{
    return NULL;
}
node*root=new node(d);
root->left=builttree();
root->right=builttree();
if(root->left!=NULL && i==0)
    {
    if(root->data < root->left->data)
    {
        cout<<root->data<<" "<<root->left->data<<" ";
        i++;
    }
    }
    if(root->right!=NULL && i==0)
    {
      if(root->data > root->right->data)
    {
        cout<<root->data<<" "<<root->left->data<<" ";
        i++;
    }  
    }
return root;

}
// void recoverTree(node* root) {
// if(root==NULL)
// {
// return;
// }

// recoverTree(root->left);
// recoverTree(root->right);
// return;
// }
int main() {
/* code here /
i=0;
noderoot=builttree();
// recoverTree(root);
return 0;
}
it only pass one test case can you plzz tell me what the mistake in this code

#2

Hey @Pranav7g
Please share your code in Coding blocks IDE

#3
#4

Hey @Pranav7g
Here is a testcase for which your code will not even run : 4 10 -1 -1 6 -1 2 -1 -1

Here is the algorithm:

  1. Construct inorder traversal of the tree. It should be an almost sorted list where only two elements are swapped.
  2. Identify two swapped elements x and y in an almost sorted array in linear time.
#5

why my code is wrong

#6

Make tree for the above example and you will understand.
Any 2 nodes can be swapped

1 Like
#7

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