Question

For this BST tree

Sample input: 10 ,12 5 15 2 513 22 1 14 k

Why does this give me a timed out error(possibly infinite loop)

public static int findClosestValueInBst(BST tree, int target) {
if(tree.value == target) return tree.value;
   int temp = tree.value;
       while(tree != null){
           if(Math.abs(temp - target) > Math.abs(target - tree.value)){
               temp = tree.value;
           }
           if(target < tree.value){
               tree = tree.left;
           }
          
           else if(target > tree.value) {
               tree = tree.right;
           }
       }
return temp;
}

But this one doesnt

public static int findClosestValueInBst(BST tree, int target) {
if(tree.value == target) return tree.value;
       BST next = tree;
   int temp = tree.value;
       while(next != null){
           if(Math.abs(temp - target) > Math.abs(target - next.value)){
               temp = next.value;
           }
           if(target < tree.value){
               next = next.left;
           }
          
           else if(target > tree.value) {
               next = next.right;
           }
       }
return temp;
}

Answer 1

Answer:

In your code, in each iteration of the loop, value of tree is updated based on the if else condition. That means if value of target is less than tree.value then, value of tree will be tree.left otherwise tree will be tree.right. While in other code, Value of tree is not updated in any iteration and value of next is updated with next.left or next.right. And we are also loosing the pointer of root node of tree because the value of head pointer is continuously changing in each iteration.