Amazon Interview Question for SDE-2s


Team: Product Details Page
Country: India
Interview Type: In-Person




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1
of 1 vote

public TreeNode FindCloset(TreeNode root, int value)
{
    TreeNode current = root;
    TreeNode minNode = null;
    int minValue = int.MaxValue;

    while (current != null)
    {
        int diff = Math.Abs(current.Value - value);
        if (diff < minValue)
        {
            minValue = diff;
            minNode = current;
            if (diff == 0)
                break;
        }

        current = (value < current.Value) ? current.Left : current.Right;
    }

    return minNode;
}

- hnatsu March 04, 2016 | Flag Reply
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0
of 0 vote

how about this

void findNearestNode(tree* root, int num, tree *outNode, int *out){
	if (root == NULL) return;
	if (*out > abs(root->data - num)){
		*out = abs(root->data - num);
		outNode->data = root->data;
	}
	if (num < root->data) 
		findNearestNode(root->left, num, outNode, out);
	else
		findNearestNode(root->right, num, outNode, out);
}

int main(){
	tree nd;
	int out = INT_MAX;
	findNearestNode(root, 34, &nd, &out);
	return 0;
}

- praveen pandit March 05, 2016 | Flag Reply
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0
of 0 vote

Node closestNodeValuetoK( Node root, Node prev, int K){
 //edge case
 if( root == null)
  return root;
 if(root.data == K){
   int upClosest = prev != null ? Math.abs(prev.data - K):Integer.MAXVALUE;
   int leftClosest = root.left != null ? Math.abs(root.left.data - K):Integer.MAXVALUE;
   int rightClosest = root.right != null ? Math.abs(root.right.data - K):Integer.MAXVALUE;
   // closest node
  int closest = Math.min( upClosest, Math.min( leftClosest, rightClosest ) );
  // edge case
  if( closest == Integer.MAXVALUE ) return null;
  else{
      if( closest = upClosest ) return prev;
      else if ( closest == leftClosest ) return root.left;
       else return root.right;
      }
   } 
   if ( K < root.data) // iterate left
     return closestNodeValuetoK ( root.left, root, K);
   else // iterate right
     return closestNodeValuetoK ( root.right, root, K);
}

- Anonymous March 07, 2016 | Flag Reply
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0
of 0 vote

public int getClosestValue(Node n, int value) {
		if (value > n.value) {
			if (n.right == null) {
				return n.value;
			}
			else {
				int subClosest = getClosestValue(n.right, value);
				if (Math.abs(subClosest - value) > Math.abs(n.value - value)) {
					return n.value;
				}
				return subClosest;
			}
		}
		else {
			if (n.left == null) {
				return n.value;
			}
			else {
				int subClosest = getClosestValue(n.left, value);
				if (Math.abs(subClosest - value) > Math.abs(n.value - value)) {
					return n.value;
				}
				return subClosest;
			}
		}
	}

- Sumeet Singhal March 07, 2016 | Flag Reply
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0
of 0 vote

struct bstnode* get_closest_value(struct bstnode* root, int k)
      {
         struct bstnode* node;
         if (root == NULL) return root;

         if (root->data == k) return root;
         else if (root->data < k)
         {
            if (root->left == NULL) return root;
            else
            {

               node = get_closest_value(root->left, k);
               return(abs(node->data - k) > abs(root->data - k) ? root : node);
            }
         }
         else
         {
            if (root->right == NULL) return root;
            else
            {
               node = get_closest_value(root->right, k);
               return(abs(node->data - k) > abs(root->data - k) ? root : node);
            }
         }
      }

- ms March 10, 2016 | Flag Reply
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0
of 0 vote

I am wondering that the K is Integer or float?

- Anonymous March 11, 2016 | Flag Reply
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0
of 0 vote

int closestToK(TreeNode * root, int k)
{
	if (root -> val == k)
		return root -> val;
	int l, r, used_l = 0, used_r = 0;
	if (root -> left){
		used_l = 1;
		l = closestToK(root -> left, k);
	}
	if (root -> right){
		used_r = 1;
		r = closestToK(root -> right, k);
	}
	int result = root -> val;
	if (used_l && abs(result - k) > abs(l - k))
		result = l;
	if (used_r && abs(result - k) > abs(r - k))
		result = r;
	return result;
}
int closest_main(TreeNode * root, int k){
	if (!root)
		return 0;
	else	
		return closestToK(root, k);
}

- kuiwy7 March 15, 2016 | Flag Reply
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0
of 0 vote

Use binary search algorithm and keep tracking the lower bound and upper bound as goes deep into the tree. If found in the tree it works just like binary search. Otherwise hitting the bottom of the tree, compare its distance with the lower bound and upper bound. Pick the bound with smaller distance. Details: cpluspluslearning-petert.blogspot.co.uk/2016/03/bst-find-closest-value.html

Two implementations: recursive and non-recursive.

Test

void TestFindCloesetNode_R()
{
    TreeNode<double> *root = NULL;
    assert(FindClosetNode_R(root, 0.0) == NULL);

    std::vector<double> input = { 1.0 };
    root = ConstructTreeRecursive(input);
    assert(root);
    TreeNode<double> *foundNode = FindClosetNode_R(root, 1.0);
    assert(*foundNode->data == 1.0);
    foundNode = FindClosetNode_R(root, 100.0);
    assert(*foundNode->data == 1.0);
    foundNode = FindClosetNode_R(root, -100.0);
    assert(*foundNode->data == 1.0);
    DeleteTree_BU(&root);

    input = { 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, 12.0, 13.0, 14.0, 15.0, 16.0 };
    root = ConstructTreeOnSortedValueBFS(input);
    assert(root);
    foundNode = FindClosetNode_R(root, -100.0);
    assert(*foundNode->data == 1.0);
    foundNode = FindClosetNode_R(root, -1.0);
    assert(*foundNode->data == 1.0);
    foundNode = FindClosetNode_R(root, -1.0);
    assert(*foundNode->data == 1.0);
    foundNode = FindClosetNode_R(root, 1.2);
    assert(*foundNode->data == 1.0);
    foundNode = FindClosetNode_R(root, 1.6);
    assert(*foundNode->data == 2.0);
    foundNode = FindClosetNode_R(root, 2.0);
    assert(*foundNode->data == 2.0);
    foundNode = FindClosetNode_R(root, 2.1);
    assert(*foundNode->data == 2.0);
    foundNode = FindClosetNode_R(root, 2.6);
    assert(*foundNode->data == 3.0);
    foundNode = FindClosetNode_R(root, 3.0);
    assert(*foundNode->data == 3.0);
    foundNode = FindClosetNode_R(root, 3.4);
    assert(*foundNode->data == 3.0);
    foundNode = FindClosetNode_R(root, 3.6);
    assert(*foundNode->data == 4.0);
    foundNode = FindClosetNode_R(root, 4.0);
    assert(*foundNode->data == 4.0);
    foundNode = FindClosetNode_R(root, 4.4);
    assert(*foundNode->data == 4.0);
    foundNode = FindClosetNode_R(root, 4.6);
    assert(*foundNode->data == 5.0);
    foundNode = FindClosetNode_R(root, 5.0);
    assert(*foundNode->data == 5.0);
    foundNode = FindClosetNode_R(root, 5.3);
    assert(*foundNode->data == 5.0);
    foundNode = FindClosetNode_R(root, 5.6);
    assert(*foundNode->data == 6.0);
    foundNode = FindClosetNode_R(root, 6.0);
    assert(*foundNode->data == 6.0);
    foundNode = FindClosetNode_R(root, 6.3);
    assert(*foundNode->data == 6.0);
    foundNode = FindClosetNode_R(root, 6.6);
    assert(*foundNode->data == 7.0);
    foundNode = FindClosetNode_R(root, 7.0);
    assert(*foundNode->data == 7.0);
    foundNode = FindClosetNode_R(root, 7.3);
    assert(*foundNode->data == 7.0);
    foundNode = FindClosetNode_R(root, 7.6);
    assert(*foundNode->data == 8.0);
    foundNode = FindClosetNode_R(root, 8.0);
    assert(*foundNode->data == 8.0);
    foundNode = FindClosetNode_R(root, 8.3);
    assert(*foundNode->data == 8.0);
    foundNode = FindClosetNode_R(root, 8.6);
    assert(*foundNode->data == 9.0);
    foundNode = FindClosetNode_R(root, 9.0);
    assert(*foundNode->data == 9.0);
    foundNode = FindClosetNode_R(root, 9.3);
    assert(*foundNode->data == 9.0);
    foundNode = FindClosetNode_R(root, 9.6);
    assert(*foundNode->data == 10.0);
    foundNode = FindClosetNode_R(root, 10.0);
    assert(*foundNode->data == 10.0);
    foundNode = FindClosetNode_R(root, 10.3);
    assert(*foundNode->data == 10.0);
    foundNode = FindClosetNode_R(root, 10.6);
    assert(*foundNode->data == 11.0);
    foundNode = FindClosetNode_R(root, 11.0);
    assert(*foundNode->data == 11.0);
    foundNode = FindClosetNode_R(root, 11.3);
    assert(*foundNode->data == 11.0);
    foundNode = FindClosetNode_R(root, 11.6);
    assert(*foundNode->data == 12.0);
    foundNode = FindClosetNode_R(root, 12.0);
    assert(*foundNode->data == 12.0);
    foundNode = FindClosetNode_R(root, 12.3);
    assert(*foundNode->data == 12.0);
    foundNode = FindClosetNode_R(root, 12.6);
    assert(*foundNode->data == 13.0);
    foundNode = FindClosetNode_R(root, 13.0);
    assert(*foundNode->data == 13.0);
    foundNode = FindClosetNode_R(root, 13.3);
    assert(*foundNode->data == 13.0);
    foundNode = FindClosetNode_R(root, 13.6);
    assert(*foundNode->data == 14.0);
    foundNode = FindClosetNode_R(root, 14.0);
    assert(*foundNode->data == 14.0);
    foundNode = FindClosetNode_R(root, 14.3);
    assert(*foundNode->data == 14.0);
    foundNode = FindClosetNode_R(root, 14.6);
    assert(*foundNode->data == 15.0);
    foundNode = FindClosetNode_R(root, 15.0);
    assert(*foundNode->data == 15.0);
    foundNode = FindClosetNode_R(root, 15.3);
    assert(*foundNode->data == 15.0);
    foundNode = FindClosetNode_R(root, 15.6);
    assert(*foundNode->data == 16.0);
    foundNode = FindClosetNode_R(root, 16.0);
    assert(*foundNode->data == 16.0);
    foundNode = FindClosetNode_R(root, 16.3);
    assert(*foundNode->data == 16.0);
    foundNode = FindClosetNode_R(root, 100.0);
    assert(*foundNode->data == 16.0);
    DeleteTree_TD(&root);
}

void TestFindCloesetNode()
{
    TreeNode<double> *root = NULL;
    assert(FindClosetNode(root, 0.0) == NULL);

    std::vector<double> input = { 1.0 };
    root = ConstructTreeRecursive(input);
    assert(root);
    TreeNode<double> *foundNode = FindClosetNode(root, 1.0);
    assert(*foundNode->data == 1.0);
    foundNode = FindClosetNode(root, 100.0);
    assert(*foundNode->data == 1.0);
    foundNode = FindClosetNode(root, -100.0);
    assert(*foundNode->data == 1.0);
    DeleteTree_BU(&root);

    input = { 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, 12.0, 13.0, 14.0, 15.0, 16.0 };
    root = ConstructTreeOnSortedValueBFS(input);
    assert(root);
    foundNode = FindClosetNode(root, -100.0);
    assert(*foundNode->data == 1.0);
    foundNode = FindClosetNode(root, -1.0);
    assert(*foundNode->data == 1.0);
    foundNode = FindClosetNode(root, -1.0);
    assert(*foundNode->data == 1.0);
    foundNode = FindClosetNode(root, 1.2);
    assert(*foundNode->data == 1.0);
    foundNode = FindClosetNode(root, 1.6);
    assert(*foundNode->data == 2.0);
    foundNode = FindClosetNode(root, 2.0);
    assert(*foundNode->data == 2.0);
    foundNode = FindClosetNode(root, 2.1);
    assert(*foundNode->data == 2.0);
    foundNode = FindClosetNode(root, 2.6);
    assert(*foundNode->data == 3.0);
    foundNode = FindClosetNode(root, 3.0);
    assert(*foundNode->data == 3.0);
    foundNode = FindClosetNode(root, 3.4);
    assert(*foundNode->data == 3.0);
    foundNode = FindClosetNode(root, 3.6);
    assert(*foundNode->data == 4.0);
    foundNode = FindClosetNode(root, 4.0);
    assert(*foundNode->data == 4.0);
    foundNode = FindClosetNode(root, 4.4);
    assert(*foundNode->data == 4.0);
    foundNode = FindClosetNode(root, 4.6);
    assert(*foundNode->data == 5.0);
    foundNode = FindClosetNode(root, 5.0);
    assert(*foundNode->data == 5.0);
    foundNode = FindClosetNode(root, 5.3);
    assert(*foundNode->data == 5.0);
    foundNode = FindClosetNode(root, 5.6);
    assert(*foundNode->data == 6.0);
    foundNode = FindClosetNode(root, 6.0);
    assert(*foundNode->data == 6.0);
    foundNode = FindClosetNode(root, 6.3);
    assert(*foundNode->data == 6.0);
    foundNode = FindClosetNode(root, 6.6);
    assert(*foundNode->data == 7.0);
    foundNode = FindClosetNode(root, 7.0);
    assert(*foundNode->data == 7.0);
    foundNode = FindClosetNode(root, 7.3);
    assert(*foundNode->data == 7.0);
    foundNode = FindClosetNode(root, 7.6);
    assert(*foundNode->data == 8.0);
    foundNode = FindClosetNode(root, 8.0);
    assert(*foundNode->data == 8.0);
    foundNode = FindClosetNode(root, 8.3);
    assert(*foundNode->data == 8.0);
    foundNode = FindClosetNode(root, 8.6);
    assert(*foundNode->data == 9.0);
    foundNode = FindClosetNode(root, 9.0);
    assert(*foundNode->data == 9.0);
    foundNode = FindClosetNode(root, 9.3);
    assert(*foundNode->data == 9.0);
    foundNode = FindClosetNode(root, 9.6);
    assert(*foundNode->data == 10.0);
    foundNode = FindClosetNode(root, 10.0);
    assert(*foundNode->data == 10.0);
    foundNode = FindClosetNode(root, 10.3);
    assert(*foundNode->data == 10.0);
    foundNode = FindClosetNode(root, 10.6);
    assert(*foundNode->data == 11.0);
    foundNode = FindClosetNode(root, 11.0);
    assert(*foundNode->data == 11.0);
    foundNode = FindClosetNode(root, 11.3);
    assert(*foundNode->data == 11.0);
    foundNode = FindClosetNode(root, 11.6);
    assert(*foundNode->data == 12.0);
    foundNode = FindClosetNode(root, 12.0);
    assert(*foundNode->data == 12.0);
    foundNode = FindClosetNode(root, 12.3);
    assert(*foundNode->data == 12.0);
    foundNode = FindClosetNode(root, 12.6);
    assert(*foundNode->data == 13.0);
    foundNode = FindClosetNode(root, 13.0);
    assert(*foundNode->data == 13.0);
    foundNode = FindClosetNode(root, 13.3);
    assert(*foundNode->data == 13.0);
    foundNode = FindClosetNode(root, 13.6);
    assert(*foundNode->data == 14.0);
    foundNode = FindClosetNode(root, 14.0);
    assert(*foundNode->data == 14.0);
    foundNode = FindClosetNode_R(root, 14.3);
    assert(*foundNode->data == 14.0);
    foundNode = FindClosetNode(root, 14.6);
    assert(*foundNode->data == 15.0);
    foundNode = FindClosetNode(root, 15.0);
    assert(*foundNode->data == 15.0);
    foundNode = FindClosetNode(root, 15.3);
    assert(*foundNode->data == 15.0);
    foundNode = FindClosetNode(root, 15.6);
    assert(*foundNode->data == 16.0);
    foundNode = FindClosetNode(root, 16.0);
    assert(*foundNode->data == 16.0);
    foundNode = FindClosetNode(root, 16.3);
    assert(*foundNode->data == 16.0);
    foundNode = FindClosetNode(root, 100.0);
    assert(*foundNode->data == 16.0);
    DeleteTree_TD(&root);
}

- peter tang March 21, 2016 | Flag Reply
Comment hidden because of low score. Click to expand.
0
of 0 vote

public int bstClosestValue(int k) {
		int closest = _bstClosestValue(bst, k);
		System.out.println("Closes : " + closest);
		return closest;
	}
	
	private int _bstClosestValue(TreeNode node, int k) {
		int closest = node.data;
		int prediff = Math.abs(node.data - k);
		Stack<TreeNode> stack = new Stack<TreeNode>();
		while (!stack.isEmpty() || node != null) {
			if (node != null) {
				stack.push(node);
				node = node.left;
			} else {
				node = stack.pop();
				int currdiff = Math.abs(node.data - k);
				if (currdiff < prediff) {
					closest = node.data;
					prediff = currdiff;
				}
				node = node.right;
			}
		}
		return closest;
	}

- Anonymous June 04, 2016 | Flag Reply


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