1818public class ClosestBinarySearchTreeValue {
1919
2020 /**
21- * @param node
22- * @param parentNode
23- * @param val
24- * @param diff
21+ * Runtime: <a href="https://leetcode.com/submissions/detail/248841443/">0 ms</a>.
22+ *
23+ * @param root
24+ * @param target
2525 * @return
2626 */
27- public static TreeNode findNodeWithClosestValue (TreeNode node , TreeNode parentNode , int val , int diff ) {
28- if (node == null ) return parentNode ;
27+ public static int closestValue (TreeNode root , double target ) {
28+ if (root == null ) return - 1 ;
2929
30- if (Math .abs (node .val - val ) > diff ) return parentNode ;
30+ return closestValue (root , root , target );
31+ }
32+ 33+ private static int closestValue (TreeNode node , TreeNode closestNode , double val ) {
34+ if (node == null ) return closestNode .val ;
35+ 36+ if (Math .abs (node .val - val ) < Math .abs (closestNode .val - val )) {
37+ closestNode = node ;
38+ }
3139
3240 if (node .val > val ) {
33- return findNodeWithClosestValue (node .left , node , val , Math . abs ( node . val - val ) );
41+ return closestValue (node .left , closestNode , val );
3442 } else {
35- return findNodeWithClosestValue (node .right , node , val , Math . abs ( node . val - val ) );
43+ return closestValue (node .right , closestNode , val );
3644 }
3745 }
3846
@@ -54,17 +62,17 @@ public static void main(String[] args) {
5462 root .right = new TreeNode (13 );
5563 root .left .left = new TreeNode (5 );
5664 root .left .right = new TreeNode (8 );
57- root .left .left .left = new TreeNode (2 );
5865 root .left .left .right = new TreeNode (6 );
66+ root .left .left .left = new TreeNode (2 );
5967 root .right .right = new TreeNode (20 );
6068
61- assertEquals (13 , findNodeWithClosestValue (root , root , 15 , Integer . MAX_VALUE ). val );
62- assertEquals (13 , findNodeWithClosestValue (root , root , 13 , Integer . MAX_VALUE ). val );
63- assertEquals (9 , findNodeWithClosestValue (root , root , 9 , Integer . MAX_VALUE ). val );
64- assertEquals (2 , findNodeWithClosestValue (root , root , 2 , Integer . MAX_VALUE ). val );
65- assertEquals (2 , findNodeWithClosestValue (root , root , 1 , Integer . MAX_VALUE ). val );
66- assertEquals (6 , findNodeWithClosestValue (root , root , 6 , Integer . MAX_VALUE ). val );
67- assertEquals (13 , findNodeWithClosestValue (root , root , 11 , Integer . MAX_VALUE ). val ); // tie b/w 9 and 13
69+ assertEquals (13 , closestValue (root , 15 ) );
70+ assertEquals (13 , closestValue (root , 13 ) );
71+ assertEquals (9 , closestValue (root , 9 ) );
72+ assertEquals (2 , closestValue (root , 2 ) );
73+ assertEquals (2 , closestValue (root , 1 ) );
74+ assertEquals (6 , closestValue (root , 6 ) );
75+ assertEquals (13 , closestValue (root , 11 ) ); // tie b/w 9 and 13
6876
6977 /*
7078 BST looks like:
@@ -83,6 +91,20 @@ public static void main(String[] args) {
8391 root .right .left = new TreeNode (13 );
8492 root .right .right = new TreeNode (20 );
8593
86- assertEquals (13 , findNodeWithClosestValue (root , root , 15 , Integer .MAX_VALUE ).val );
94+ assertEquals (13 , closestValue (root , 15 ));
95+ 96+ /*
97+ BST looks like:
98+
99+ 1500000000
100+ /
101+ /
102+ /
103+ 1400000000
104+ */
105+ root = new TreeNode (1500000000 );
106+ root .left = new TreeNode (1400000000 );
107+ 108+ assertEquals (1400000000 , closestValue (root , -1500000000.0 ));
87109 }
88110}
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