Create 1038-binary-search-tree-to-greater-sum-tree.js

Author: everthis

1038-binary-search-tree-to-greater-sum-tree.js

@@ -0,0 +1,28 @@
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val) {
+ *     this.val = val;
+ *     this.left = this.right = null;
+ * }
+ */
+/**
+ * @param {TreeNode} root
+ * @return {TreeNode}
+ */
+const bstToGst = function(root) {
+  const arr = []
+  dfs(root, arr)
+  let v = 0
+  for(let i = arr.length - 1; i >= 0; i--) {
+    arr[i].val = arr[i].val + v
+    v = arr[i].val
+  }
+  return root
+};
+
+function dfs(node, arr) {
+  if(node == null) return
+  dfs(node.left, arr)
+  arr.push(node)
+  dfs(node.right, arr)
+}