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Kth_Ancestor.cpp
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Kth_Ancestor.cpp
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#include<iostream>
#include<climits>
using namespace std;
class Node{
public:
int data;
Node* left;
Node* right;
Node(int val)
{
data = val;
left = NULL;
right = NULL;
}
};
void printBT(const std::string& prefix, const Node* node, bool isLeft)
{
if (node != nullptr)
{
std::cout << prefix;
std::cout << (isLeft ? "|--" : "L--");
std::cout << node->data << std::endl;
printBT(prefix + (isLeft ? "| " : " "), node->right, true);
printBT(prefix + (isLeft ? "| " : " "), node->left, false);
}
}
void printBT(const Node* node)
{
printBT("", node, false);
}
Node* KthAncestor(Node* root,int n, int &k)
{
if(root==NULL)
return NULL;
if(root->data==n)
return root;
Node* leftNode = KthAncestor(root->left, n, k);
Node* rightNode = KthAncestor(root->right, n, k);
if(leftNode!=NULL && rightNode==NULL)
{
k--;
if(k<=0)
{
k==INT_MAX;
return root;
}
return leftNode;
}
if(leftNode==NULL && rightNode!=NULL)
{
k--;
if(k<=0)
{
k=INT_MAX;
return root;
}
return rightNode;
}
return NULL;
}
int main()
{
Node* root = new Node(1);
root->left = new Node(2);
root->left->left = new Node(4);
root->left->right = new Node(5);
root->right = new Node(3);
int k=2;
cout<<KthAncestor(root, 4,k)->data;
return 0;
}