add leetcode 783

Author: betomoedano

binary-trees/783-minimum-distance-between-bst-nodes.js

@@ -0,0 +1,48 @@
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val, left, right) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.left = (left===undefined ? null : left)
+ *     this.right = (right===undefined ? null : right)
+ * }
+ */
+/**
+ * @param {TreeNode} root
+ * @return {number}
+ * Time O(n) where n is the number of nodes
+ * Space O(h) where h is the hight of the tree
+ */
+
+// We create a class to keep track of the minimum height difference and the previous node
+class TreeNodeInfo {
+  constructor(minHeightDiff, prevNode) {
+    this.minHeightDiff = minHeightDiff;
+    this.prevNode = prevNode;
+  }
+}
+
+// This function returns the minimum height difference of a binary search tree
+function getMinimumHeightDiff(root) {
+  const treeNodeInfo = new TreeNodeInfo(Infinity, null); // Initialize minimum height difference to be infinity and previous node to be null
+  traverseInOrder(root, treeNodeInfo); // Start traversing the tree in order
+  return treeNodeInfo.minHeightDiff; // Return minimum height difference after traversing the tree
+}
+
+// This function traverses a binary search tree in order and updates the minimum height difference and previous node information
+function traverseInOrder(node, treeNodeInfo) {
+  if (node === null) return; // Base case
+
+  traverseInOrder(node.left, treeNodeInfo); // Traverse left subtree
+
+  if (treeNodeInfo.prevNode !== null) {
+    // If previous node is not null, update the minimum height difference
+    treeNodeInfo.minHeightDiff = Math.min(
+      treeNodeInfo.minHeightDiff,
+      node.val - treeNodeInfo.prevNode.val
+    );
+  }
+
+  treeNodeInfo.prevNode = node; // Update previous node to be the current node
+
+  traverseInOrder(node.right, treeNodeInfo); // Traverse right subtree
+}