Create 979-distribute-coins-in-binary-tree.js

Author: everthis

979-distribute-coins-in-binary-tree.js

@@ -0,0 +1,25 @@
+/**
+ * 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}
+ */
+const distributeCoins = function(root) {
+  let res = 0
+  helper(root)
+  return res
+  
+  function helper(node) {
+    if(node == null) return 0
+    const left = helper(node.left)
+    const right = helper(node.right)
+    res += Math.abs(left) + Math.abs(right)
+    return node.val + left + right - 1
+  }
+};