Given a root of a tree, and an integer k. Print all the nodes which are at k distance from root.
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void printKDistant(node *root , int k) { if(root == NULL) return; if( k == 0 ) { printf( "%d ", root->data ); return ; } else { printKDistant( root->left, k-1 ) ; printKDistant( root->right, k-1 ) ; }}