update: find all ancestors of a node

Author: ashokdey

src/_DataStructures_/Trees/BinarySearchTree/find-ancestors/index.js

@@ -0,0 +1,43 @@
+// eslint-disable-next-line no-unused-vars
+const BST = require('../index');
+
+function findAncestors(root, value) {
+  /**
+   * search the given node and meanwhile
+   * keep pushing the visited nodes
+   */
+  let arr = [];
+  if (root === null) return [];
+  if (value > root.value) {
+    // traverse right
+    const left = findAncestors(root.rightChild, value);
+    arr = [...arr, ...left];
+  }
+  if (value < root.value) {
+    // traverse left
+    const right = findAncestors(root.leftChild, value);
+    arr = [...arr, ...right];
+  }
+  if (root.value === value) return arr;
+  arr = [root.value, ...arr];
+  return arr;
+}
+
+// create a BST
+// const myBST = new BST(6);
+// myBST.add(4);
+// myBST.add(9);
+// myBST.add(2);
+// myBST.add(5);
+// myBST.add(14);
+// myBST.add(8);
+// myBST.add(12);
+// myBST.add(10);
+
+// // find 3rd max
+// // console.log(myBST.root);
+// console.log(myBST.traversePreorder());
+// // console.log(myBST.root.rightChild);
+// console.log(findAncestors(myBST.root, 10));
+
+module.exports = findAncestors;